Merge

.hgtags

@@ -369,3 +369,4 @@ d53037a90c441cb528dc41c30827985de0e67c62 jdk-9+123
 2a5697a98620c4f40e4a1a71478464399b8878de jdk-9+124
 3aa52182b3ad7c5b3a61cf05a59dd07e4c5884e5 jdk-9+125
 03e7b2c5ae345be3caf981d76ceb3efe5ff447f8 jdk-9+126
+8e45018bde9de4ad15b972ae62874bba52dba2d5 jdk-9+127

.hgtags-top-repo

@@ -369,3 +369,4 @@ cae471d3b87783e0a3deea658e1e1c84b2485b6c jdk-9+121
 f80c841ae2545eaf9acd2724bccc305d98cefbe2 jdk-9+124
 9aa7d40f3a453f51e47f4c1b19eff5740a74a9f8 jdk-9+125
 3a58466296d36944454756ef01e7513ac5e14a16 jdk-9+126
+8fa686245bd2a072ece3392743460030f0854520 jdk-9+127

corba/.hgtags

@@ -369,3 +369,4 @@ e33a34cc551907617d8129c4faaf1a5a7e61d21c jdk-9+123
 45121d5afb9d5bfadab75378572ad96832e0809e jdk-9+124
 1d48e67d1b91eb9f72e49e69a4021edb85e357fc jdk-9+125
 c7f5ba08fcd4b8416e62c21229f9a07c95498919 jdk-9+126
+8fab452b6f4710762ba1d8e55fd62db00b1355fe jdk-9+127

hotspot/.hgtags

@@ -529,3 +529,4 @@ af6b4ad908e732d23021f12e8322b204433d5cf6 jdk-9+122
 479631362b4930be985245ea063d87d821a472eb jdk-9+124
 bb640b49741af3f57f9994129934c46fc173219f jdk-9+125
 adc8c84b7cf8c540d920182f78a2bc982366432a jdk-9+126
+352357128f602dcf0426b1cbe011a4685a4d9f97 jdk-9+127

hotspot/make/gensrc/GensrcDtrace.gmk

@@ -45,7 +45,8 @@ ifeq ($(call check-jvm-feature, dtrace), true)
   $(DTRACE_GENSRC_DIR)/%.h: $(DTRACE_SOURCE_DIR)/%.d
 	$(call LogInfo, Generating dtrace header file $(@F))
 	$(call MakeDir, $(@D) $(DTRACE_SUPPORT_DIR))
-	$(call ExecuteWithLog, $(DTRACE_SUPPORT_DIR)/$(@F).d, $(CC) -E $(DTRACE_CPP_FLAGS) $< > $(DTRACE_SUPPORT_DIR)/$(@F).d)
+	$(call ExecuteWithLog, $(DTRACE_SUPPORT_DIR)/$(@F).d, \
+	    ( $(CC) -E $(DTRACE_CPP_FLAGS) $< > $(DTRACE_SUPPORT_DIR)/$(@F).d ) )
 	$(call ExecuteWithLog, $@, $(DTRACE) $(DTRACE_FLAGS) -h -o $@ -s $(DTRACE_SUPPORT_DIR)/$(@F).d)
 
   # Process all .d files in DTRACE_SOURCE_DIR. They are:

hotspot/make/lib/CompileDtracePostJvm.gmk

@@ -68,7 +68,7 @@ ifeq ($(call check-jvm-feature, dtrace), true)
       $1: $$(BUILD_DTRACE_GEN_OFFSETS)
 	$$(call LogInfo, Generating dtrace $2 file $$(@F))
 	$$(call MakeDir, $$(@D))
-	$$(call ExecuteWithLog, $$@, $$(DTRACE_GEN_OFFSETS_TOOL) -$$(strip $2) > $$@)
+	$$(call ExecuteWithLog, $$@, ( $$(DTRACE_GEN_OFFSETS_TOOL) -$$(strip $2) > $$@ ) )
 
       TARGETS += $1
     endef

hotspot/src/share/tools/LogCompilation/src/com/sun/hotspot/tools/compiler/UncommonTrap.java

@@ -16,9 +16,9 @@
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
- * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
- * CA 95054 USA or visit www.sun.com if you need additional information or
- * have any questions.
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
  *
  */
 package com.sun.hotspot.tools.compiler;

hotspot/src/share/vm/classfile/classLoaderData.cpp

@@ -501,13 +501,26 @@ ClassLoaderData::~ClassLoaderData() {
   }
 }
 
-/**
- * Returns true if this class loader data is for the platform class loader.
- */
+// Returns true if this class loader data is for the system class loader.
+bool ClassLoaderData::is_system_class_loader_data() const {
+  return SystemDictionary::is_system_class_loader(class_loader());
+}
+
+// Returns true if this class loader data is for the platform class loader.
 bool ClassLoaderData::is_platform_class_loader_data() const {
   return SystemDictionary::is_platform_class_loader(class_loader());
 }
 
+// Returns true if this class loader data is one of the 3 builtin
+// (boot, application/system or platform) class loaders. Note, the
+// builtin loaders are not freed by a GC.
+bool ClassLoaderData::is_builtin_class_loader_data() const {
+  Handle classLoaderHandle = class_loader();
+  return (is_the_null_class_loader_data() ||
+          SystemDictionary::is_system_class_loader(classLoaderHandle) ||
+          SystemDictionary::is_platform_class_loader(classLoaderHandle));
+}
+
 Metaspace* ClassLoaderData::metaspace_non_null() {
   assert(!DumpSharedSpaces, "wrong metaspace!");
   // If the metaspace has not been allocated, create a new one.  Might want
@@ -957,12 +970,6 @@ bool ClassLoaderDataGraph::do_unloading(BoolObjectClosure* is_alive_closure,
   data = _head;
   while (data != NULL) {
     if (data->is_alive(is_alive_closure)) {
-      if (data->packages_defined()) {
-        data->packages()->purge_all_package_exports();
-      }
-      if (data->modules_defined()) {
-        data->modules()->purge_all_module_reads();
-      }
       // clean metaspace
       if (walk_all_metadata) {
         data->classes_do(InstanceKlass::purge_previous_versions);
@@ -990,6 +997,23 @@ bool ClassLoaderDataGraph::do_unloading(BoolObjectClosure* is_alive_closure,
   }
 
   if (seen_dead_loader) {
+    // Walk a ModuleEntry's reads and a PackageEntry's exports lists
+    // to determine if there are modules on those lists that are now
+    // dead and should be removed.  A module's life cycle is equivalent
+    // to its defining class loader's life cycle.  Since a module is
+    // considered dead if its class loader is dead, these walks must
+    // occur after each class loader's aliveness is determined.
+    data = _head;
+    while (data != NULL) {
+      if (data->packages_defined()) {
+        data->packages()->purge_all_package_exports();
+      }
+      if (data->modules_defined()) {
+        data->modules()->purge_all_module_reads();
+      }
+      data = data->next();
+    }
+
     post_class_unload_events();
   }
 

hotspot/src/share/vm/classfile/classLoaderData.hpp

@@ -270,7 +270,9 @@ class ClassLoaderData : public CHeapObj<mtClass> {
   bool is_the_null_class_loader_data() const {
     return this == _the_null_class_loader_data;
   }
+  bool is_system_class_loader_data() const;
   bool is_platform_class_loader_data() const;
+  bool is_builtin_class_loader_data() const;
 
   // The Metaspace is created lazily so may be NULL.  This
   // method will allocate a Metaspace if needed.

hotspot/src/share/vm/classfile/compactHashtable.cpp

@@ -248,7 +248,7 @@ inline void SimpleCompactHashtable::iterate(const I& iterator) {
     } else {
       u4*entry_max = _entries + BUCKET_OFFSET(_buckets[i + 1]);
       while (entry < entry_max) {
-        iterator.do_value(_base_address, entry[0]);
+        iterator.do_value(_base_address, entry[1]);
         entry += 2;
       }
     }

hotspot/src/share/vm/classfile/moduleEntry.cpp

@@ -40,7 +40,6 @@
 
 ModuleEntry* ModuleEntryTable::_javabase_module = NULL;
 
-
 void ModuleEntry::set_location(Symbol* location) {
   if (_location != NULL) {
     // _location symbol's refcounts are managed by ModuleEntry,
@@ -115,10 +114,35 @@ void ModuleEntry::add_read(ModuleEntry* m) {
       // Lazily create a module's reads list
       _reads = new (ResourceObj::C_HEAP, mtModule)GrowableArray<ModuleEntry*>(MODULE_READS_SIZE, true);
     }
+
+    // Determine, based on this newly established read edge to module m,
+    // if this module's read list should be walked at a GC safepoint.
+    set_read_walk_required(m->loader_data());
+
+    // Establish readability to module m
     _reads->append_if_missing(m);
   }
 }
 
+// If the module's loader, that a read edge is being established to, is
+// not the same loader as this module's and is not one of the 3 builtin
+// class loaders, then this module's reads list must be walked at GC
+// safepoint. Modules have the same life cycle as their defining class
+// loaders and should be removed if dead.
+void ModuleEntry::set_read_walk_required(ClassLoaderData* m_loader_data) {
+  assert_locked_or_safepoint(Module_lock);
+  if (!_must_walk_reads &&
+      loader_data() != m_loader_data &&
+      !m_loader_data->is_builtin_class_loader_data()) {
+    _must_walk_reads = true;
+    if (log_is_enabled(Trace, modules)) {
+      ResourceMark rm;
+      log_trace(modules)("ModuleEntry::set_read_walk_required(): module %s reads list must be walked",
+                         (name() != NULL) ? name()->as_C_string() : UNNAMED_MODULE);
+    }
+  }
+}
+
 bool ModuleEntry::has_reads() const {
   assert_locked_or_safepoint(Module_lock);
   return ((_reads != NULL) && !_reads->is_empty());
@@ -127,14 +151,28 @@ bool ModuleEntry::has_reads() const {
 // Purge dead module entries out of reads list.
 void ModuleEntry::purge_reads() {
   assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
-  if (has_reads()) {
+
+  if (_must_walk_reads && has_reads()) {
+    // This module's _must_walk_reads flag will be reset based
+    // on the remaining live modules on the reads list.
+    _must_walk_reads = false;
+
+    if (log_is_enabled(Trace, modules)) {
+      ResourceMark rm;
+      log_trace(modules)("ModuleEntry::purge_reads(): module %s reads list being walked",
+                         (name() != NULL) ? name()->as_C_string() : UNNAMED_MODULE);
+    }
+
     // Go backwards because this removes entries that are dead.
     int len = _reads->length();
     for (int idx = len - 1; idx >= 0; idx--) {
       ModuleEntry* module_idx = _reads->at(idx);
-      ClassLoaderData* cld = module_idx->loader();
-      if (cld->is_unloading()) {
+      ClassLoaderData* cld_idx = module_idx->loader_data();
+      if (cld_idx->is_unloading()) {
         _reads->delete_at(idx);
+      } else {
+        // Update the need to walk this module's reads based on live modules
+        set_read_walk_required(cld_idx);
       }
     }
   }
@@ -248,7 +286,7 @@ ModuleEntry* ModuleEntryTable::new_entry(unsigned int hash, Handle module_handle
     entry->set_module(loader_data->add_handle(module_handle));
   }
 
-  entry->set_loader(loader_data);
+  entry->set_loader_data(loader_data);
   entry->set_version(version);
   entry->set_location(location);
 
@@ -375,11 +413,11 @@ void ModuleEntryTable::print(outputStream* st) {
 
 void ModuleEntry::print(outputStream* st) {
   ResourceMark rm;
-  st->print_cr("entry "PTR_FORMAT" name %s module "PTR_FORMAT" loader %s version %s location %s strict %s next "PTR_FORMAT,
+  st->print_cr("entry " PTR_FORMAT " name %s module " PTR_FORMAT " loader %s version %s location %s strict %s next " PTR_FORMAT,
                p2i(this),
                name() == NULL ? UNNAMED_MODULE : name()->as_C_string(),
                p2i(module()),
-               loader()->loader_name(),
+               loader_data()->loader_name(),
                version() != NULL ? version()->as_C_string() : "NULL",
                location() != NULL ? location()->as_C_string() : "NULL",
                BOOL_TO_STR(!can_read_all_unnamed()), p2i(next()));
@@ -401,5 +439,5 @@ void ModuleEntryTable::verify() {
 }
 
 void ModuleEntry::verify() {
-  guarantee(loader() != NULL, "A module entry must be associated with a loader.");
+  guarantee(loader_data() != NULL, "A module entry must be associated with a loader.");
 }

hotspot/src/share/vm/classfile/moduleEntry.hpp

@@ -43,6 +43,7 @@ class ModuleClosure;
 // It contains:
 //   - Symbol* containing the module's name.
 //   - pointer to the java.lang.reflect.Module for this module.
+//   - pointer to the java.security.ProtectionDomain shared by classes defined to this module.
 //   - ClassLoaderData*, class loader of this module.
 //   - a growable array containg other module entries that this module can read.
 //   - a flag indicating if this module can read all unnamed modules.
@@ -54,56 +55,58 @@ private:
   jobject _module;                     // java.lang.reflect.Module
   jobject _pd;                         // java.security.ProtectionDomain, cached
                                        // for shared classes from this module
-  ClassLoaderData* _loader;
+  ClassLoaderData* _loader_data;
   GrowableArray<ModuleEntry*>* _reads; // list of modules that are readable by this module
   Symbol* _version;                    // module version number
   Symbol* _location;                   // module location
   bool _can_read_all_unnamed;
   bool _has_default_read_edges;        // JVMTI redefine/retransform support
+  bool _must_walk_reads;               // walk module's reads list at GC safepoints to purge out dead modules
   TRACE_DEFINE_TRACE_ID_FIELD;
   enum {MODULE_READS_SIZE = 101};      // Initial size of list of modules that the module can read.
 
 public:
   void init() {
     _module = NULL;
-    _loader = NULL;
+    _loader_data = NULL;
     _pd = NULL;
     _reads = NULL;
     _version = NULL;
     _location = NULL;
     _can_read_all_unnamed = false;
     _has_default_read_edges = false;
+    _must_walk_reads = false;
   }
 
-  Symbol*            name() const          { return literal(); }
-  void               set_name(Symbol* n)   { set_literal(n); }
+  Symbol*          name() const          { return literal(); }
+  void             set_name(Symbol* n)   { set_literal(n); }
 
-  jobject            module() const        { return _module; }
-  void               set_module(jobject j) { _module = j; }
+  jobject          module() const        { return _module; }
+  void             set_module(jobject j) { _module = j; }
 
   // The shared ProtectionDomain reference is set once the VM loads a shared class
   // originated from the current Module. The referenced ProtectionDomain object is
   // created by the ClassLoader when loading a class (shared or non-shared) from the
   // Module for the first time. This ProtectionDomain object is used for all
   // classes from the Module loaded by the same ClassLoader.
-  Handle             shared_protection_domain();
-  void               set_shared_protection_domain(ClassLoaderData *loader_data,
-                                                  Handle pd);
+  Handle           shared_protection_domain();
+  void             set_shared_protection_domain(ClassLoaderData *loader_data, Handle pd);
 
-  ClassLoaderData*   loader() const                 { return _loader; }
-  void               set_loader(ClassLoaderData* l) { _loader = l; }
+  ClassLoaderData* loader_data() const                 { return _loader_data; }
+  void             set_loader_data(ClassLoaderData* l) { _loader_data = l; }
 
-  Symbol*            version() const                { return _version; }
-  void               set_version(Symbol* version);
+  Symbol*          version() const                     { return _version; }
+  void             set_version(Symbol* version);
 
-  Symbol*            location() const               { return _location; }
-  void               set_location(Symbol* location);
+  Symbol*          location() const                    { return _location; }
+  void             set_location(Symbol* location);
 
-  bool               can_read(ModuleEntry* m) const;
-  bool               has_reads() const;
-  void               add_read(ModuleEntry* m);
+  bool             can_read(ModuleEntry* m) const;
+  bool             has_reads() const;
+  void             add_read(ModuleEntry* m);
+  void             set_read_walk_required(ClassLoaderData* m_loader_data);
 
-  bool               is_named() const               { return (literal() != NULL); }
+  bool             is_named() const                    { return (name() != NULL); }
 
   bool can_read_all_unnamed() const {
     assert(is_named() || _can_read_all_unnamed == true,
@@ -178,7 +181,7 @@ private:
   ModuleEntry* _unnamed_module;
 
   ModuleEntry* new_entry(unsigned int hash, Handle module_handle, Symbol* name, Symbol* version,
-                         Symbol* location, ClassLoaderData* class_loader);
+                         Symbol* location, ClassLoaderData* loader_data);
   void add_entry(int index, ModuleEntry* new_entry);
 
   int entry_size() const { return BasicHashtable<mtModule>::entry_size(); }

hotspot/src/share/vm/classfile/modules.cpp

@@ -113,7 +113,7 @@ static PackageEntry* get_package_entry(ModuleEntry* module_entry, jstring packag
   const char *package_name = java_lang_String::as_utf8_string(JNIHandles::resolve_non_null(package));
   if (package_name == NULL) return NULL;
   TempNewSymbol pkg_symbol = SymbolTable::new_symbol(package_name, CHECK_NULL);
-  PackageEntryTable* package_entry_table = module_entry->loader()->packages();
+  PackageEntryTable* package_entry_table = module_entry->loader_data()->packages();
   assert(package_entry_table != NULL, "Unexpected null package entry table");
   return package_entry_table->lookup_only(pkg_symbol);
 }
@@ -868,7 +868,7 @@ void Modules::add_module_package(jobject module, jstring package, TRAPS) {
                      package_name, module_entry->name()->as_C_string());
 
   TempNewSymbol pkg_symbol = SymbolTable::new_symbol(package_name, CHECK);
-  PackageEntryTable* package_table = module_entry->loader()->packages();
+  PackageEntryTable* package_table = module_entry->loader_data()->packages();
   assert(package_table != NULL, "Missing package_table");
 
   bool pkg_exists = false;

hotspot/src/share/vm/classfile/packageEntry.cpp

@@ -25,6 +25,7 @@
 #include "precompiled.hpp"
 #include "classfile/moduleEntry.hpp"
 #include "classfile/packageEntry.hpp"
+#include "logging/log.hpp"
 #include "memory/resourceArea.hpp"
 #include "oops/symbol.hpp"
 #include "runtime/handles.inline.hpp"
@@ -53,12 +54,40 @@ void PackageEntry::add_qexport(ModuleEntry* m) {
   if (!has_qual_exports_list()) {
     // Lazily create a package's qualified exports list.
     // Initial size is small, do not anticipate export lists to be large.
-    _qualified_exports =
-      new (ResourceObj::C_HEAP, mtModule) GrowableArray<ModuleEntry*>(QUAL_EXP_SIZE, true);
+    _qualified_exports = new (ResourceObj::C_HEAP, mtModule) GrowableArray<ModuleEntry*>(QUAL_EXP_SIZE, true);
   }
+
+  // Determine, based on this newly established export to module m,
+  // if this package's export list should be walked at a GC safepoint.
+  set_export_walk_required(m->loader_data());
+
+  // Establish exportability to module m
   _qualified_exports->append_if_missing(m);
 }
 
+// If the module's loader, that an export is being established to, is
+// not the same loader as this module's and is not one of the 3 builtin
+// class loaders, then this package's export list must be walked at GC
+// safepoint. Modules have the same life cycle as their defining class
+// loaders and should be removed if dead.
+void PackageEntry::set_export_walk_required(ClassLoaderData* m_loader_data) {
+  assert_locked_or_safepoint(Module_lock);
+  ModuleEntry* this_pkg_mod = module();
+  if (!_must_walk_exports &&
+      (this_pkg_mod == NULL || this_pkg_mod->loader_data() != m_loader_data) &&
+      !m_loader_data->is_builtin_class_loader_data()) {
+    _must_walk_exports = true;
+    if (log_is_enabled(Trace, modules)) {
+      ResourceMark rm;
+      assert(name() != NULL, "PackageEntry without a valid name");
+      log_trace(modules)("PackageEntry::set_export_walk_required(): package %s defined in module %s, exports list must be walked",
+                         name()->as_C_string(),
+                         (this_pkg_mod == NULL || this_pkg_mod->name() == NULL) ?
+                           UNNAMED_MODULE : this_pkg_mod->name()->as_C_string());
+    }
+  }
+}
+
 // Set the package's exported states based on the value of the ModuleEntry.
 void PackageEntry::set_exported(ModuleEntry* m) {
   MutexLocker m1(Module_lock);
@@ -96,14 +125,34 @@ void PackageEntry::set_is_exported_allUnnamed() {
 // Remove dead module entries within the package's exported list.
 void PackageEntry::purge_qualified_exports() {
   assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
-  if (_qualified_exports != NULL) {
+  if (_must_walk_exports &&
+      _qualified_exports != NULL &&
+      !_qualified_exports->is_empty()) {
+    ModuleEntry* pkg_module = module();
+
+    // This package's _must_walk_exports flag will be reset based
+    // on the remaining live modules on the exports list.
+    _must_walk_exports = false;
+
+    if (log_is_enabled(Trace, modules)) {
+      ResourceMark rm;
+      assert(name() != NULL, "PackageEntry without a valid name");
+      ModuleEntry* pkg_mod = module();
+      log_trace(modules)("PackageEntry::purge_qualified_exports(): package %s defined in module %s, exports list being walked",
+                         name()->as_C_string(),
+                         (pkg_mod == NULL || pkg_mod->name() == NULL) ? UNNAMED_MODULE : pkg_mod->name()->as_C_string());
+    }
+
     // Go backwards because this removes entries that are dead.
     int len = _qualified_exports->length();
     for (int idx = len - 1; idx >= 0; idx--) {
       ModuleEntry* module_idx = _qualified_exports->at(idx);
-      ClassLoaderData* cld = module_idx->loader();
-      if (cld->is_unloading()) {
+      ClassLoaderData* cld_idx = module_idx->loader_data();
+      if (cld_idx->is_unloading()) {
         _qualified_exports->delete_at(idx);
+      } else {
+        // Update the need to walk this package's exports based on live modules
+        set_export_walk_required(cld_idx);
       }
     }
   }
@@ -297,8 +346,8 @@ void PackageEntryTable::print(outputStream* st) {
 
 void PackageEntry::print(outputStream* st) {
   ResourceMark rm;
-  st->print_cr("package entry "PTR_FORMAT" name %s module %s classpath_index "
-               INT32_FORMAT " is_exported_unqualified %d is_exported_allUnnamed %d " "next "PTR_FORMAT,
+  st->print_cr("package entry " PTR_FORMAT " name %s module %s classpath_index "
+               INT32_FORMAT " is_exported_unqualified %d is_exported_allUnnamed %d " "next " PTR_FORMAT,
                p2i(this), name()->as_C_string(),
                (module()->is_named() ? module()->name()->as_C_string() : UNNAMED_MODULE),
                _classpath_index, _is_exported_unqualified, _is_exported_allUnnamed, p2i(next()));

hotspot/src/share/vm/classfile/packageEntry.hpp

@@ -69,6 +69,7 @@ private:
   s2 _classpath_index;
   bool _is_exported_unqualified;
   bool _is_exported_allUnnamed;
+  bool _must_walk_exports;
   GrowableArray<ModuleEntry*>* _exported_pending_delete; // transitioned from qualified to unqualified, delete at safepoint
   GrowableArray<ModuleEntry*>* _qualified_exports;
   TRACE_DEFINE_TRACE_ID_FIELD;
@@ -82,6 +83,7 @@ public:
     _classpath_index = -1;
     _is_exported_unqualified = false;
     _is_exported_allUnnamed = false;
+    _must_walk_exports = false;
     _exported_pending_delete = NULL;
     _qualified_exports = NULL;
   }
@@ -147,6 +149,7 @@ public:
 
   // add the module to the package's qualified exports
   void add_qexport(ModuleEntry* m);
+  void set_export_walk_required(ClassLoaderData* m_loader_data);
 
   PackageEntry* next() const {
     return (PackageEntry*)HashtableEntry<Symbol*, mtModule>::next();

hotspot/src/share/vm/classfile/systemDictionary.cpp

@@ -175,9 +175,18 @@ bool SystemDictionary::is_parallelDefine(Handle class_loader) {
    return false;
 }
 
-/**
- * Returns true if the passed class loader is the platform class loader.
- */
+// Returns true if the passed class loader is the builtin application class loader
+// or a custom system class loader. A customer system class loader can be
+// specified via -Djava.system.class.loader.
+bool SystemDictionary::is_system_class_loader(Handle class_loader) {
+  if (class_loader.is_null()) {
+    return false;
+  }
+  return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() ||
+          class_loader() == _java_system_loader);
+}
+
+// Returns true if the passed class loader is the platform class loader.
 bool SystemDictionary::is_platform_class_loader(Handle class_loader) {
   if (class_loader.is_null()) {
     return false;

hotspot/src/share/vm/classfile/systemDictionary.hpp

@@ -660,6 +660,7 @@ public:
   static instanceKlassHandle load_shared_class(Symbol* class_name,
                                                Handle class_loader,
                                                TRAPS);
+  static bool is_system_class_loader(Handle class_loader);
   static bool is_platform_class_loader(Handle class_loader);
 
 protected:

hotspot/src/share/vm/gc/shared/preservedMarks.cpp

@@ -48,10 +48,10 @@ void PreservedMarks::restore_and_increment(volatile size_t* const total_size_add
 
 #ifndef PRODUCT
 void PreservedMarks::assert_empty() {
-  assert(_stack.is_empty(), "stack expected to be empty, size = "SIZE_FORMAT,
+  assert(_stack.is_empty(), "stack expected to be empty, size = " SIZE_FORMAT,
          _stack.size());
   assert(_stack.cache_size() == 0,
-         "stack expected to have no cached segments, cache size = "SIZE_FORMAT,
+         "stack expected to have no cached segments, cache size = " SIZE_FORMAT,
          _stack.cache_size());
 }
 #endif // ndef PRODUCT

hotspot/src/share/vm/interpreter/rewriter.cpp

@@ -419,21 +419,20 @@ void Rewriter::scan_method(Method* method, bool reverse, bool* invokespecial_err
             InstanceKlass* klass = method->method_holder();
             u2 bc_index = Bytes::get_Java_u2(bcp + prefix_length + 1);
             constantPoolHandle cp(method->constants());
-            Symbol* field_name = cp->name_ref_at(bc_index);
-            Symbol* field_sig = cp->signature_ref_at(bc_index);
             Symbol* ref_class_name = cp->klass_name_at(cp->klass_ref_index_at(bc_index));
 
             if (klass->name() == ref_class_name) {
+              Symbol* field_name = cp->name_ref_at(bc_index);
+              Symbol* field_sig = cp->signature_ref_at(bc_index);
+
               fieldDescriptor fd;
               klass->find_field(field_name, field_sig, &fd);
               if (fd.access_flags().is_final()) {
                 if (fd.access_flags().is_static()) {
-                  assert(c == Bytecodes::_putstatic, "must be putstatic");
                   if (!method->is_static_initializer()) {
                     fd.set_has_initialized_final_update(true);
                   }
                 } else {
-                  assert(c == Bytecodes::_putfield, "must be putfield");
                   if (!method->is_object_initializer()) {
                     fd.set_has_initialized_final_update(true);
                   }

hotspot/src/share/vm/runtime/arguments.cpp

@@ -584,27 +584,26 @@ static bool verify_special_jvm_flags() {
 // Parses a size specification string.
 bool Arguments::atojulong(const char *s, julong* result) {
   julong n = 0;
-  int args_read = 0;
-  bool is_hex = false;
-  // Skip leading 0[xX] for hexadecimal
-  if (*s =='0' && (*(s+1) == 'x' || *(s+1) == 'X')) {
-    s += 2;
-    is_hex = true;
-    args_read = sscanf(s, JULONG_FORMAT_X, &n);
-  } else {
-    args_read = sscanf(s, JULONG_FORMAT, &n);
-  }
-  if (args_read != 1) {
+
+  // First char must be a digit. Don't allow negative numbers or leading spaces.
+  if (!isdigit(*s)) {
     return false;
   }
-  while (*s != '\0' && (isdigit(*s) || (is_hex && isxdigit(*s)))) {
-    s++;
-  }
-  // 4705540: illegal if more characters are found after the first non-digit
-  if (strlen(s) > 1) {
+
+  bool is_hex = (s[0] == '0' && (s[1] == 'x' || s[1] == 'X'));
+  char* remainder;
+  errno = 0;
+  n = strtoull(s, &remainder, (is_hex ? 16 : 10));
+  if (errno != 0) {
     return false;
   }
-  switch (*s) {
+
+  // Fail if no number was read at all or if the remainder contains more than a single non-digit character.
+  if (remainder == s || strlen(remainder) > 1) {
+    return false;
+  }
+
+  switch (*remainder) {
     case 'T': case 't':
       *result = n * G * K;
       // Check for overflow.

hotspot/src/share/vm/utilities/vmError.cpp

@@ -205,16 +205,39 @@ void VMError::print_stack_trace(outputStream* st, JavaThread* jt,
 static void print_oom_reasons(outputStream* st) {
   st->print_cr("# Possible reasons:");
   st->print_cr("#   The system is out of physical RAM or swap space");
-  st->print_cr("#   In 32 bit mode, the process size limit was hit");
+  if (UseCompressedOops) {
+    st->print_cr("#   The process is running with CompressedOops enabled, and the Java Heap may be blocking the growth of the native heap");
+  }
+  if (LogBytesPerWord == 2) {
+    st->print_cr("#   In 32 bit mode, the process size limit was hit");
+  }
   st->print_cr("# Possible solutions:");
   st->print_cr("#   Reduce memory load on the system");
   st->print_cr("#   Increase physical memory or swap space");
   st->print_cr("#   Check if swap backing store is full");
-  st->print_cr("#   Use 64 bit Java on a 64 bit OS");
+  if (LogBytesPerWord == 2) {
+    st->print_cr("#   Use 64 bit Java on a 64 bit OS");
+  }
   st->print_cr("#   Decrease Java heap size (-Xmx/-Xms)");
   st->print_cr("#   Decrease number of Java threads");
   st->print_cr("#   Decrease Java thread stack sizes (-Xss)");
   st->print_cr("#   Set larger code cache with -XX:ReservedCodeCacheSize=");
+  if (UseCompressedOops) {
+    switch (Universe::narrow_oop_mode()) {
+      case Universe::UnscaledNarrowOop:
+        st->print_cr("#   JVM is running with Unscaled Compressed Oops mode in which the Java heap is");
+        st->print_cr("#     placed in the first 4GB address space. The Java Heap base address is the");
+        st->print_cr("#     maximum limit for the native heap growth. Please use -XX:HeapBaseMinAddress");
+        st->print_cr("#     to set the Java Heap base and to place the Java Heap above 4GB virtual address.");
+        break;
+      case Universe::ZeroBasedNarrowOop:
+        st->print_cr("#   JVM is running with Zero Based Compressed Oops mode in which the Java heap is");
+        st->print_cr("#     placed in the first 32GB address space. The Java Heap base address is the");
+        st->print_cr("#     maximum limit for the native heap growth. Please use -XX:HeapBaseMinAddress");
+        st->print_cr("#     to set the Java Heap base and to place the Java Heap above 32GB virtual address.");
+        break;
+    }
+  }
   st->print_cr("# This output file may be truncated or incomplete.");
 }
 

hotspot/test/TEST.groups

@@ -395,6 +395,17 @@ hotspot_jprt = \
   :hotspot_fast_gc_gcold \
   :hotspot_fast_runtime \
   :hotspot_fast_serviceability
+  
+hotspot_runtime_tier2 = \
+  runtime/ \
+  serviceability/ \
+ -:hotspot_fast_runtime \
+ -:hotspot_fast_serviceability \
+ -:hotspot_runtime_tier2_platform_agnostic
+ 
+hotspot_runtime_tier2_platform_agnostic = \
+  runtime/SelectionResolution \
+ -:hotspot_fast_runtime
 
 #All tests that depends on nashorn extension.
 #

hotspot/test/gc/g1/humongousObjects/TestNoAllocationsInHRegions.java

@@ -0,0 +1,234 @@
+/*
+ * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+package gc.g1.humongousObjects;
+
+import jdk.test.lib.Utils;
+import sun.hotspot.WhiteBox;
+
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Random;
+import java.util.stream.Collectors;
+
+/**
+ * @test TestNoAllocationsInHRegions
+ * @summary Checks that no additional allocations are made in humongous regions
+ * @requires vm.gc.G1
+ * @library /testlibrary /test/lib /
+ * @modules java.management java.base/jdk.internal.misc
+ * @build sun.hotspot.WhiteBox
+ *        gc.testlibrary.Helpers
+ *        gc.g1.humongousObjects.TestNoAllocationsInHRegions
+ *
+ * @run driver ClassFileInstaller sun.hotspot.WhiteBox
+ *      sun.hotspot.WhiteBox$WhiteBoxPermission
+ *
+ * @run main/othervm -XX:+UseG1GC -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -Xbootclasspath/a:.
+ *                   -XX:G1HeapRegionSize=1M -Xms200m -Xmx200m -XX:MaxTenuringThreshold=0
+ *                   -Xlog:gc=trace:file=TestNoAllocationsInHRegions10.log
+ *                   gc.g1.humongousObjects.TestNoAllocationsInHRegions 30 10
+ *
+ * @run main/othervm -XX:+UseG1GC -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -Xbootclasspath/a:.
+ *                   -XX:G1HeapRegionSize=1M -Xms200m -Xmx200m -XX:MaxTenuringThreshold=0
+ *                   -Xlog:gc=trace:file=TestNoAllocationsInHRegions50.log
+ *                   gc.g1.humongousObjects.TestNoAllocationsInHRegions 30 50
+ *
+ * @run main/othervm -XX:+UseG1GC -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -Xbootclasspath/a:.
+ *                   -XX:G1HeapRegionSize=1M -Xms200m -Xmx200m -XX:MaxTenuringThreshold=0
+ *                   -Xlog:gc=trace:file=TestNoAllocationsInHRegions70.log
+ *                   gc.g1.humongousObjects.TestNoAllocationsInHRegions 30 70
+ */
+public class TestNoAllocationsInHRegions {
+    private static final WhiteBox WB = WhiteBox.getWhiteBox();
+    private static final Random RND = Utils.getRandomInstance();
+    private static final int G1_REGION_SIZE = WB.g1RegionSize();
+    private static final int[] HUMONGOUS_SIZES = {G1_REGION_SIZE / 2, G1_REGION_SIZE + 1, G1_REGION_SIZE * 2 + 1};
+    private static final int ALLOC_THREAD_COUNT = 5;
+
+    // We fill specified part of heap with humongous objects - we need public static to prevent escape analysis to
+    // collect this field
+    public static LinkedList<byte[]> humongousAllocations = new LinkedList<>();
+
+    private static volatile boolean shouldStop = false;
+    private static volatile Error error = null;
+
+    static class Allocator implements Runnable {
+
+        private final List<byte[]> liveObjects = new LinkedList<>();
+        private int usedMemory = 0;
+        public final Runnable[] actions;
+
+        /**
+         * Maximum size of simple allocation
+         */
+        private static final int MAX_ALLOCATION_SIZE = (int) (G1_REGION_SIZE / 2 * 0.9);
+
+        /**
+         * Maximum size of dead (i.e. one which is made unreachable right after allocation) object
+         */
+        private static final int DEAD_OBJECT_MAX_SIZE = G1_REGION_SIZE / 10;
+
+        public Allocator(int maxAllocationMemory) {
+
+            actions = new Runnable[]{
+                    // Allocation
+                    () -> {
+                        if (maxAllocationMemory - usedMemory != 0) {
+                            int arraySize = RND.nextInt(Math.min(maxAllocationMemory - usedMemory,
+                                    MAX_ALLOCATION_SIZE));
+
+                            if (arraySize != 0) {
+                                byte[] allocation = new byte[arraySize];
+                                liveObjects.add(allocation);
+                                usedMemory += arraySize;
+
+                                // Sanity check
+                                if (WB.g1IsHumongous(allocation)) {
+                                    String errorMessage = String.format("Test Bug: Byte array of size"
+                                                    + " %d is expected to be non-humongous but it is humongous",
+                                            allocation.length);
+
+                                    System.out.println(errorMessage);
+                                    error = new Error(errorMessage);
+                                    shouldStop = true;
+                                }
+
+                                // Test check
+                                if (WB.g1BelongsToHumongousRegion(WB.getObjectAddress(allocation))) {
+                                    String errorMessage = String.format("Non-humongous allocation of byte array of "
+                                            + "length %d and size %d with address %d was made in Humongous Region",
+                                            allocation.length, WB.getObjectSize(allocation),
+                                            WB.getObjectAddress(allocation));
+
+                                    System.out.println(errorMessage);
+                                    error = new Error(errorMessage);
+                                    shouldStop = true;
+                                }
+                            }
+                        }
+                    },
+
+                    // Deallocation
+                    () -> {
+                        if (liveObjects.size() != 0) {
+                            int elementNum = RND.nextInt(liveObjects.size());
+                            int shouldFree = liveObjects.get(elementNum).length;
+                            liveObjects.remove(elementNum);
+                            usedMemory -= shouldFree;
+                        }
+                    },
+
+                    // Dead object allocation
+                    () -> {
+                        int size = RND.nextInt(DEAD_OBJECT_MAX_SIZE);
+                        byte[] deadObject = new byte[size];
+                    },
+
+                    // Check
+                    () -> {
+                        List<byte[]> wrongHumongousAllocations = liveObjects.stream()
+                                .filter(WB::g1IsHumongous)
+                                .collect(Collectors.toList());
+
+                        if (wrongHumongousAllocations.size() > 0) {
+                            wrongHumongousAllocations.stream().forEach(a ->
+                                    System.out.format("Non-humongous allocation of byte array of length %d and"
+                                                    + " size %d with address %d was made in Humongous Region",
+                                            a.length, WB.getObjectSize(a), WB.getObjectAddress(a)));
+                            error = new Error("Some non-humongous allocations were made to humongous region");
+                            shouldStop = true;
+                        }
+                    }
+            };
+        }
+
+        @Override
+        public void run() {
+            while (!shouldStop) {
+                actions[RND.nextInt(actions.length)].run();
+                Thread.yield();
+            }
+        }
+    }
+
+    public static void main(String[] args) {
+        if (args.length != 2) {
+            throw new Error("Test Bug: Expected duration (in seconds) and percent of allocated regions were not "
+                    + "provided as command line argument");
+        }
+
+        // test duration
+        long duration = Integer.parseInt(args[0]) * 1000L;
+        // part of heap preallocated with humongous objects (in percents)
+        int percentOfAllocatedHeap = Integer.parseInt(args[1]);
+
+        long startTime = System.currentTimeMillis();
+
+        long initialFreeRegionsCount = WB.g1NumFreeRegions();
+        int regionsToAllocate = (int) ((double) initialFreeRegionsCount / 100.0 * percentOfAllocatedHeap);
+        long freeRegionLeft = initialFreeRegionsCount - regionsToAllocate;
+
+        System.out.println("Regions to allocate: " + regionsToAllocate + "; regions to left free: " + freeRegionLeft);
+
+        int maxMemoryPerAllocThread = (int) ((Runtime.getRuntime().freeMemory() / 100.0
+                * (100 - percentOfAllocatedHeap)) / ALLOC_THREAD_COUNT * 0.5);
+
+        System.out.println("Using " + maxMemoryPerAllocThread / 1024 + "KB for each of " + ALLOC_THREAD_COUNT
+                + " allocation threads");
+
+        while (WB.g1NumFreeRegions() > freeRegionLeft) {
+            try {
+                humongousAllocations.add(new byte[HUMONGOUS_SIZES[RND.nextInt(HUMONGOUS_SIZES.length)]]);
+            } catch (OutOfMemoryError oom) {
+                //We got OOM trying to fill heap with humongous objects
+                //It probably means that heap is fragmented which is strange since the test logic should avoid it
+                System.out.println("Warning: OOM while allocating humongous objects - it likely means "
+                        + "that heap is fragmented");
+                break;
+            }
+        }
+
+        System.out.println("Initial free regions " + initialFreeRegionsCount + "; Free regions left "
+                + WB.g1NumFreeRegions());
+
+        LinkedList<Thread> threads = new LinkedList<>();
+
+        for (int i = 0; i < ALLOC_THREAD_COUNT; i++) {
+            threads.add(new Thread(new Allocator(maxMemoryPerAllocThread)));
+        }
+
+        threads.stream().forEach(Thread::start);
+
+        while ((System.currentTimeMillis() - startTime < duration) && error == null) {
+            Thread.yield();
+        }
+
+        shouldStop = true;
+        System.out.println("Finished test");
+        if (error != null) {
+            throw error;
+        }
+    }
+}

hotspot/test/gc/g1/humongousObjects/objectGraphTest/GC.java

@@ -138,6 +138,41 @@ public enum GC {
         }
     },
 
+    MIXED_GC {
+        @Override
+        public Runnable get() {
+            return () -> {
+                WHITE_BOX.youngGC();
+                Helpers.waitTillCMCFinished(WHITE_BOX, 0);
+                WHITE_BOX.youngGC();
+                Helpers.waitTillCMCFinished(WHITE_BOX, 0);
+
+                WHITE_BOX.g1StartConcMarkCycle();
+                Helpers.waitTillCMCFinished(WHITE_BOX, 0);
+
+                WHITE_BOX.youngGC();
+                Helpers.waitTillCMCFinished(WHITE_BOX, 0);
+                // Provoking Mixed GC
+                WHITE_BOX.youngGC();// second evacuation pause will be mixed
+                Helpers.waitTillCMCFinished(WHITE_BOX, 0);
+            };
+        }
+
+        public Consumer<ReferenceInfo<Object[]>> getChecker() {
+            return getCheckerImpl(true, false, true, false);
+        }
+
+        @Override
+        public List<String> shouldContain() {
+            return Arrays.asList(GCTokens.WB_INITIATED_CMC);
+        }
+
+        @Override
+        public List<String> shouldNotContain() {
+            return Arrays.asList(GCTokens.YOUNG_GC);
+        }
+    },
+
     FULL_GC_MEMORY_PRESSURE {
         @Override
         public Runnable get() {

hotspot/test/gc/g1/humongousObjects/objectGraphTest/README

@@ -38,6 +38,9 @@ The test checks that after different type of GC unreachable objects behave as ex
                         non-humongous and humongous objects are not collected since we make 2 Young GC to promote all
                         weak references to Old Gen.
 
+6. Mixed GC - weakly referenced non-humongous and humongous objects are collected, softly referenced non-humongous and
+              humongous objects are not collected.
+
 The test gets gc type as a command line argument.
 Then the test allocates object graph in heap (currently testing scenarios are pre-generated and stored in
 TestcaseData.getPregeneratedTestcases()) with TestObjectGraphAfterGC::allocateObjectGraph.

hotspot/test/gc/g1/humongousObjects/objectGraphTest/TestObjectGraphAfterGC.java

@@ -66,6 +66,12 @@ import java.util.stream.Collectors;
  *                                sun.hotspot.WhiteBox$WhiteBoxPermission
  *
  * @run main/othervm -Xms200M -XX:+UseG1GC -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -Xbootclasspath/a:.
+ * -XX:+UnlockExperimentalVMOptions -XX:MaxGCPauseMillis=30000 -XX:G1MixedGCLiveThresholdPercent=100 -XX:G1HeapWastePercent=0
+ * -XX:G1HeapRegionSize=1M -Xlog:gc=info:file=TestObjectGraphAfterGC_MIXED_GC.gc.log -XX:MaxTenuringThreshold=1
+ * -XX:G1MixedGCCountTarget=1  -XX:G1OldCSetRegionThresholdPercent=100 -XX:SurvivorRatio=1 -XX:InitiatingHeapOccupancyPercent=0
+ * gc.g1.humongousObjects.objectGraphTest.TestObjectGraphAfterGC MIXED_GC
+ *
+ * @run main/othervm -Xms200M -XX:+UseG1GC -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -Xbootclasspath/a:.
  * -XX:G1HeapRegionSize=1M -Xlog:gc*=debug:file=TestObjectGraphAfterGC_YOUNG_GC.gc.log
  * gc.g1.humongousObjects.objectGraphTest.TestObjectGraphAfterGC YOUNG_GC
  *

hotspot/test/native/runtime/test_arguments.cpp

@@ -0,0 +1,71 @@
+/*
+ * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+#include "precompiled.hpp"
+#include "runtime/arguments.hpp"
+#include "unittest.hpp"
+#include "utilities/globalDefinitions.hpp"
+
+TEST(arguments, atojulong) {
+  char ullong_max[32];
+  int ret = jio_snprintf(ullong_max, sizeof(ullong_max), JULONG_FORMAT, ULLONG_MAX);
+  ASSERT_NE(-1, ret);
+
+  julong value;
+  const char* invalid_strings[] = {
+    "", "-1", "-100", " 1", "2 ", "3 2", "1.0",
+    "0x4.5", "0x", "0x0x1" "0.001", "4e10", "e"
+    "K", "M", "G", "1MB", "1KM", "AA", "0B",
+    "18446744073709551615K", "17179869184G",
+    "999999999999999999999999999999"
+  };
+  for (uint i = 0; i < ARRAY_SIZE(invalid_strings); i++) {
+    ASSERT_FALSE(Arguments::atojulong(invalid_strings[i], &value))
+        << "Invalid string '" << invalid_strings[i] << "' parsed without error.";
+  }
+
+  struct {
+    const char* str;
+    julong expected_value;
+  } valid_strings[] = {
+      { "0", 0 },
+      { "4711", 4711 },
+      { "1K", 1ULL * K },
+      { "1k", 1ULL * K },
+      { "2M", 2ULL * M },
+      { "2m", 2ULL * M },
+      { "4G", 4ULL * G },
+      { "4g", 4ULL * G },
+      { "0K", 0 },
+      { ullong_max, ULLONG_MAX },
+      { "0xcafebabe", 0xcafebabe },
+      { "0XCAFEBABE", 0xcafebabe },
+      { "0XCAFEbabe", 0xcafebabe },
+      { "0x10K", 0x10 * K }
+  };
+  for (uint i = 0; i < ARRAY_SIZE(valid_strings); i++) {
+    ASSERT_TRUE(Arguments::atojulong(valid_strings[i].str, &value))
+        << "Valid string '" << valid_strings[i].str << "' did not parse.";
+    ASSERT_EQ(valid_strings[i].expected_value, value);
+  }
+}

hotspot/test/runtime/Final/Bad.jasm

@@ -0,0 +1,55 @@
+/*
+ * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/* Recoded in jasm to provoke an ICCE assigning a non-static final field with putstatic.
+class Bad {
+  public static final int i; //rewritten
+  //rewritten to: public final int i;
+  static { i = 5; } // putstatic instruction
+}
+*/
+
+super class Bad
+	version 53:0
+{
+
+// Remove 'static' keyword
+public final Field i:I;
+
+Method "<init>":"()V"
+	stack 1 locals 1
+{
+		aload_0;
+		invokespecial	Method java/lang/Object."<init>":"()V";
+		return;
+}
+
+static Method "<clinit>":"()V"
+	stack 1 locals 0
+{
+		iconst_5;
+		putstatic	Field i:"I";
+		return;
+}
+
+} // end Class Bad

hotspot/test/runtime/Final/PutfieldError.java

@@ -0,0 +1,42 @@
+/*
+ * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test PutfieldError
+ * @bug 8160551
+ * @summary Throw ICCE rather than crashing for nonstatic final field in static initializer
+ * @compile Bad.jasm
+ * @run main PutfieldError
+ */
+
+public class PutfieldError {
+  public static void main(java.lang.String[] unused) {
+    try {
+      Bad b = new Bad();
+      System.out.println("Bad.i = " + 5);
+      throw new RuntimeException("ICCE NOT thrown as expected");
+    } catch (IncompatibleClassChangeError icce) {
+      System.out.println("ICCE thrown as expected");
+    }
+  }
+}

hotspot/test/runtime/SharedArchiveFile/SharedStringsDedup.java

@@ -0,0 +1,72 @@
+/*
+ * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test SharedStringsDedup
+ * @summary Test -Xshare:auto with shared strings and -XX:+UseStringDeduplication
+ * Feature support: G1GC only, compressed oops/kptrs, 64-bit os, not on windows
+ * @requires (sun.arch.data.model != "32") & (os.family != "windows")
+ * @requires (vm.opt.UseCompressedOops == null) | (vm.opt.UseCompressedOops == true)
+ * @requires vm.gc.G1
+ * @library /testlibrary
+ * @modules java.base/jdk.internal.misc
+ *          java.management
+ * @run main SharedStringsDedup
+ */
+
+import jdk.test.lib.*;
+import java.io.File;
+
+// The main purpose is to test the interaction between shared strings
+// and -XX:+UseStringDeduplication. We run in -Xshare:auto mode so
+// we don't need to worry about CDS archive mapping failure (which
+// doesn't happen often so it won't impact coverage).
+public class SharedStringsDedup {
+    public static void main(String[] args) throws Exception {
+        // Dump
+        ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(
+            "-XX:+UnlockDiagnosticVMOptions",
+            "-XX:SharedArchiveFile=./SharedStringsDedup.jsa",
+            "-XX:+UseCompressedOops", "-XX:+UseG1GC",
+            "-XX:+PrintSharedSpaces",
+            "-Xshare:dump");
+
+        new OutputAnalyzer(pb.start())
+            .shouldContain("Loading classes to share")
+            .shouldContain("Shared string table stats")
+            .shouldHaveExitValue(0);
+
+        // Run with -Xshare:auto
+        pb = ProcessTools.createJavaProcessBuilder(
+           "-XX:+UnlockDiagnosticVMOptions",
+           "-XX:SharedArchiveFile=./SharedStringsDedup.jsa",
+           "-XX:+UseCompressedOops", "-XX:+UseG1GC",
+           "-XX:+UseStringDeduplication",
+           "-Xshare:auto",
+           "-version");
+
+        new OutputAnalyzer(pb.start())
+            .shouldMatch("(java|openjdk) version")
+            .shouldHaveExitValue(0);
+    }
+}

hotspot/test/runtime/modules/ModuleStress/CustomSystemClassLoader.java

@@ -0,0 +1,35 @@
+/*
+ * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/**
+ * A custom system ClassLoader to define the module "m2" to during iterations of
+ * differing test runs within the test ModuleStress.java
+ */
+public class CustomSystemClassLoader extends ClassLoader {
+    public CustomSystemClassLoader() {
+        super();
+    }
+    public CustomSystemClassLoader(ClassLoader parent) {
+        super(parent);
+    }
+}

hotspot/test/runtime/modules/ModuleStress/ModuleNonBuiltinCLMain.java

@@ -0,0 +1,129 @@
+/*
+ * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+import static jdk.test.lib.Asserts.*;
+
+import java.lang.reflect.Layer;
+import java.lang.module.Configuration;
+import java.lang.module.ModuleDescriptor;
+import java.lang.module.ModuleFinder;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+
+//
+// ClassLoader1 --> defines m1 --> packages p1
+// ClassLoader2 --> defines m2 --> packages p2
+// Java System Class Loader --> defines m3 --> packages p3
+//
+// m1 can read m2
+// package p2 in m2 is exported to m1 and m3
+//
+// class p1.c1 defined in m1 tries to access p2.c2 defined in m2
+// Access allowed since m1 can read m2 and package p2 is exported to m1.
+//
+public class ModuleNonBuiltinCLMain {
+
+    // Create a Layer over the boot layer.
+    // Define modules within this layer to test access between
+    // publically defined classes within packages of those modules.
+    public void createLayerOnBoot() throws Throwable {
+
+        // Define module:     m1
+        // Can read:          java.base, m2
+        // Packages:          p1
+        // Packages exported: p1 is exported to unqualifiedly
+        ModuleDescriptor descriptor_m1 =
+                new ModuleDescriptor.Builder("m1")
+                        .requires("java.base")
+                        .requires("m2")
+                        .exports("p1")
+                        .build();
+
+        // Define module:     m2
+        // Can read:          java.base, m3
+        // Packages:          p2
+        // Packages exported: package p2 is exported to m1 and m3
+        Set<String> targets = new HashSet<>();
+        targets.add("m1");
+        targets.add("m3");
+        ModuleDescriptor descriptor_m2 =
+                new ModuleDescriptor.Builder("m2")
+                        .requires("java.base")
+                        .requires("m3")
+                        .exports("p2", targets)
+                        .build();
+
+        // Define module:     m3
+        // Can read:          java.base
+        // Packages:          p3
+        // Packages exported: none
+        ModuleDescriptor descriptor_m3 =
+                new ModuleDescriptor.Builder("m3")
+                        .requires("java.base")
+                        .build();
+
+        // Set up a ModuleFinder containing all modules for this layer.
+        ModuleFinder finder = ModuleLibrary.of(descriptor_m1, descriptor_m2, descriptor_m3);
+
+        // Resolves "m1"
+        Configuration cf = Layer.boot()
+                .configuration()
+                .resolveRequires(finder, ModuleFinder.of(), Set.of("m1"));
+
+        // map each module to differing user defined class loaders for this test
+        Map<String, ClassLoader> map = new HashMap<>();
+        Loader1 cl1 = new Loader1();
+        Loader2 cl2 = new Loader2();
+        ClassLoader cl3 = ClassLoader.getSystemClassLoader();
+        map.put("m1", cl1);
+        map.put("m2", cl2);
+        map.put("m3", cl3);
+
+        // Create Layer that contains m1 & m2
+        Layer layer = Layer.boot().defineModules(cf, map::get);
+        assertTrue(layer.findLoader("m1") == cl1);
+        assertTrue(layer.findLoader("m2") == cl2);
+        assertTrue(layer.findLoader("m3") == cl3);
+        assertTrue(layer.findLoader("java.base") == null);
+
+        // now use the same loader to load class p1.c1
+        Class p1_c1_class = cl1.loadClass("p1.c1");
+        try {
+            p1_c1_class.newInstance();
+        } catch (IllegalAccessError e) {
+            throw new RuntimeException("Test Failed, an IAE should not be thrown since p2 is exported qualifiedly to m1");
+        }
+    }
+
+    public static void main(String args[]) throws Throwable {
+      ModuleNonBuiltinCLMain test = new ModuleNonBuiltinCLMain();
+      test.createLayerOnBoot();
+    }
+
+    static class Loader1 extends ClassLoader { }
+    static class Loader2 extends ClassLoader { }
+}

hotspot/test/runtime/modules/ModuleStress/ModuleSameCLMain.java

@@ -0,0 +1,109 @@
+/*
+ * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+import static jdk.test.lib.Asserts.*;
+
+import java.lang.reflect.Layer;
+import java.lang.module.Configuration;
+import java.lang.module.ModuleDescriptor;
+import java.lang.module.ModuleFinder;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Set;
+
+//
+// ClassLoader1 --> defines m1 --> packages p1
+// ClassLoader1 --> defines m2 --> packages p2
+//
+// m1 can read m2
+// package p2 in m2 is exported to m1
+//
+// class p1.c1 defined in m1 tries to access p2.c2 defined in m2
+// Access allowed since m1 can read m2 and package p2 is exported to m1.
+//
+public class ModuleSameCLMain {
+
+    // Create a Layer over the boot layer.
+    // Define modules within this layer to test access between
+    // publically defined classes within packages of those modules.
+    public void createLayerOnBoot() throws Throwable {
+
+        // Define module:     m1
+        // Can read:          java.base, m2
+        // Packages:          p1
+        // Packages exported: p1 is exported to unqualifiedly
+        ModuleDescriptor descriptor_m1 =
+                new ModuleDescriptor.Builder("m1")
+                        .requires("java.base")
+                        .requires("m2")
+                        .exports("p1")
+                        .build();
+
+        // Define module:     m2
+        // Can read:          java.base
+        // Packages:          p2
+        // Packages exported: package p2 is exported to m1
+        ModuleDescriptor descriptor_m2 =
+                new ModuleDescriptor.Builder("m2")
+                        .requires("java.base")
+                        .exports("p2", "m1")
+                        .build();
+
+        // Set up a ModuleFinder containing all modules for this layer.
+        ModuleFinder finder = ModuleLibrary.of(descriptor_m1, descriptor_m2);
+
+        // Resolves "m1"
+        Configuration cf = Layer.boot()
+                .configuration()
+                .resolveRequires(finder, ModuleFinder.of(), Set.of("m1"));
+
+        // map each module to the same class loader for this test
+        Map<String, ClassLoader> map = new HashMap<>();
+        Loader1 cl1 = new Loader1();
+        map.put("m1", cl1);
+        map.put("m2", cl1);
+
+        // Create Layer that contains m1 & m2
+        Layer layer = Layer.boot().defineModules(cf, map::get);
+        assertTrue(layer.findLoader("m1") == cl1);
+        assertTrue(layer.findLoader("m2") == cl1);
+        assertTrue(layer.findLoader("java.base") == null);
+
+        // now use the same loader to load class p1.c1
+        Class p1_c1_class = cl1.loadClass("p1.c1");
+        try {
+            p1_c1_class.newInstance();
+        } catch (IllegalAccessError e) {
+            throw new RuntimeException("Test Failed, an IAE should not be thrown since p2 is exported qualifiedly to m1");
+        }
+    }
+
+    public static void main(String args[]) throws Throwable {
+      ModuleSameCLMain test = new ModuleSameCLMain();
+      test.createLayerOnBoot();
+    }
+
+    static class Loader1 extends ClassLoader { }
+}

hotspot/test/runtime/modules/ModuleStress/ModuleStress.java

@@ -0,0 +1,131 @@
+/*
+ * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @bug 8159262
+ * @summary Test differing scenarios where a module's readability list and a package's exportability list should be walked
+ * @modules java.base/jdk.internal.misc
+ * @library /testlibrary /test/lib
+ * @compile ../AccessCheck/ModuleLibrary.java
+ * @compile ModuleSameCLMain.java
+ * @compile ModuleNonBuiltinCLMain.java
+ * @compile CustomSystemClassLoader.java
+ * @build ModuleStress
+ * @run main/othervm ModuleStress
+ */
+
+import jdk.test.lib.*;
+import java.io.File;
+
+public class ModuleStress {
+
+    public static void main(String[] args) throws Exception {
+
+        // Test #1: java -version
+        //   All modules' readability lists and packages' exportability
+        //   lists should contain only modules defined to the 3 builtin
+        //   loaders (boot, application, platform).  Thus there is
+        //   not a need to walk those lists at a GC safepoint since
+        //   those loaders never die.
+        ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(
+             "-Xbootclasspath/a:.",
+             "-Xlog:modules=trace",
+             "-version");
+
+        OutputAnalyzer oa = new OutputAnalyzer(pb.start());
+        oa.shouldNotContain("must be walked")
+          .shouldNotContain("being walked")
+          .shouldHaveExitValue(0);
+
+        // Next 2 tests involve the use of class p1.c1 and p2.c2
+        String source1 = "package p1;"   +
+                         "import p2.c2;" +
+                         "public class c1 {" +
+                         "    public c1() {" +
+                         "       p2.c2 c2_obj = new p2.c2();" +
+                         "       c2_obj.method2();" +
+                         "   }" +
+                         "}";
+
+        String source2 = "package p2;" +
+                         "public class c2 {" +
+                         "    public void method2() { }" +
+                         "}";
+
+        ClassFileInstaller.writeClassToDisk("p2/c2",
+             InMemoryJavaCompiler.compile("p2.c2", source2),  System.getProperty("test.classes"));
+
+        ClassFileInstaller.writeClassToDisk("p1/c1",
+             InMemoryJavaCompiler.compile("p1.c1", source1), System.getProperty("test.classes"));
+
+        // Test #2: Load two modules defined to the same customer class loader.
+        //   m1's module readability list and package p2's exportability should
+        //   not be walked at a GC safepoint since both modules are defined to
+        //   the same loader and thus have the exact same life cycle.
+        pb = ProcessTools.createJavaProcessBuilder(
+             "-Xbootclasspath/a:.",
+             "-Xlog:modules=trace",
+             "ModuleSameCLMain");
+
+        oa = new OutputAnalyzer(pb.start());
+        oa.shouldNotContain("must be walked")
+          .shouldNotContain("being walked")
+          .shouldHaveExitValue(0);
+
+        // Test #3: Load two modules in differing custom class loaders.
+        //   m1's module readability list and package p2's exportability list must
+        //   be walked at a GC safepoint since both modules are defined to non-builtin
+        //   class loaders which could die and thus be unloaded.
+        pb = ProcessTools.createJavaProcessBuilder(
+             "-Xbootclasspath/a:.",
+             "-Xlog:modules=trace",
+             "ModuleNonBuiltinCLMain");
+
+        oa = new OutputAnalyzer(pb.start());
+        oa.shouldContain("module m1 reads list must be walked")
+          .shouldContain("package p2 defined in module m2, exports list must be walked")
+          .shouldNotContain("module m2 reads list must be walked")
+          .shouldHaveExitValue(0);
+
+        // Test #4: Load two modules in differing custom class loaders,
+        //   of which one has been designated as the custom system class loader
+        //   via -Djava.system.class.loader=CustomSystemClassLoader. Since
+        //   m3 is defined to the system class loader, m2's module readability
+        //   list does not have to be walked at a GC safepoint, but package p2's
+        //   exportability list does.
+        pb = ProcessTools.createJavaProcessBuilder(
+             "-Djava.system.class.loader=CustomSystemClassLoader",
+             "-Xbootclasspath/a:.",
+             "-Xlog:modules=trace",
+             "ModuleNonBuiltinCLMain");
+
+        oa = new OutputAnalyzer(pb.start());
+        oa.shouldContain("package p2 defined in module m2, exports list must be walked")
+          .shouldNotContain("module m2 reads list must be walked")
+          .shouldHaveExitValue(0);
+
+    }
+}

hotspot/test/runtime/modules/ModuleStress/ModuleStressGC.java

@@ -0,0 +1,84 @@
+/*
+ * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/**
+ * @test
+ * @bug 8159262
+ * @summary layers over the boot layer are repeatedly created, during this iteration, GCs are forced to verify correct walk of module and package lists.
+ * @modules java.base/jdk.internal.misc
+ * @library /testlibrary /test/lib
+ * @compile ../CompilerUtils.java
+ * @build ModuleStressGC
+ * @run main/othervm ModuleStressGC
+ */
+
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import jdk.test.lib.*;
+
+public class ModuleStressGC {
+
+    private static final String TEST_SRC = System.getProperty("test.src");
+    private static final String TEST_CLASSES = System.getProperty("test.classes");
+
+    private static final Path SRC_DIR = Paths.get(TEST_SRC, "src");
+    private static final Path MODS_DIR = Paths.get(TEST_CLASSES, "mods");
+
+    /**
+     * Compile two module definitions used by the test, jdk.test and jdk.translet.
+     */
+    public static void main(String[] args) throws Exception {
+
+        boolean compiled;
+        // Compile module jdk.test declaration
+        compiled = CompilerUtils.compile(
+            SRC_DIR.resolve("jdk.test"),
+            MODS_DIR.resolve("jdk.test"));
+        if (!compiled) {
+            throw new RuntimeException("Test failed to compile module jdk.test");
+        }
+
+        // Compile module jdk.translet declaration
+        compiled = CompilerUtils.compile(
+            SRC_DIR.resolve("jdk.translet"),
+            MODS_DIR.resolve("jdk.translet"),
+            "-XaddExports:jdk.test/test=jdk.translet",
+            "-mp", MODS_DIR.toString());
+        if (!compiled) {
+            throw new RuntimeException("Test failed to compile module jdk.translet");
+        }
+
+        // Sanity check that the test, jdk.test/test/MainGC.java,
+        // correctly walks module jdk.test's reads list and package
+        // test's, defined to module jdk.translet, export list at
+        // GC safepoints.
+        ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(
+            "-Xlog:modules=trace",
+            "-mp", MODS_DIR.toString(),
+            "-m", "jdk.test/test.MainGC");
+        OutputAnalyzer oa = new OutputAnalyzer(pb.start());
+        oa.shouldContain("package test defined in module jdk.test, exports list being walked")
+          .shouldContain("module jdk.test reads list being walked")
+          .shouldHaveExitValue(0);
+    }
+}

hotspot/test/runtime/modules/ModuleStress/src/jdk.test/test/MainGC.java

@@ -0,0 +1,114 @@
+/*
+ * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package test;
+
+import java.lang.module.Configuration;
+import java.lang.module.ModuleFinder;
+import java.lang.reflect.Layer;
+import java.lang.reflect.Method;
+import java.lang.reflect.Module;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.*;
+import java.util.concurrent.Callable;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
+
+public class MainGC {
+
+    private static final Path MODS_DIR = Paths.get(System.getProperty("jdk.module.path"));
+    static final String MODULE_NAME = "jdk.translet";
+
+    public static void main(String[] args) throws Exception {
+
+        ModuleFinder finder = ModuleFinder.of(MODS_DIR);
+        Layer layerBoot = Layer.boot();
+
+        Configuration cf = layerBoot
+                .configuration()
+                .resolveRequires(ModuleFinder.of(), finder, Set.of(MODULE_NAME));
+
+        Module testModule = MainGC.class.getModule();
+        ClassLoader scl = ClassLoader.getSystemClassLoader();
+
+        // Create an unique module/class loader in a layer above the boot layer.
+        // Export this module to the jdk.test/test package.
+        // Add a read edge from module jdk.test to this module.
+        Callable<Void> task = new Callable<Void>() {
+            @Override
+            public Void call() throws Exception {
+                Layer layer = Layer.boot().defineModulesWithOneLoader(cf, scl);
+                Module transletModule = layer.findModule(MODULE_NAME).get();
+                testModule.addExports("test", transletModule);
+                testModule.addReads(transletModule);
+                Class<?> c = layer.findLoader(MODULE_NAME).loadClass("translet.MainGC");
+                Method method = c.getDeclaredMethod("go");
+                method.invoke(null);
+                return null;
+            }
+        };
+
+        List<Future<Void>> results = new ArrayList<>();
+
+        // Repeatedly create the layer above stressing the exportation of
+        // package jdk.test/test to several different modules.
+        ExecutorService pool = Executors.newFixedThreadPool(Math.min(100, Runtime.getRuntime().availableProcessors()*10));
+        try {
+            for (int i = 0; i < 10000; i++) {
+                results.add(pool.submit(task));
+                // At specified intervals, force a GC. This provides an
+                // opportunity to verify that both the module jdk.test's reads
+                // and the package test's, which is defined to jdk.test, exports
+                // lists are being walked.
+                if (i == 3000 || i == 6000 || i == 9000) {
+                    System.gc();
+                }
+            }
+        } finally {
+            pool.shutdown();
+        }
+
+        int passed = 0;
+        int failed = 0;
+
+        // The failed state should be 0, the created modules in layers above the
+        // boot layer should be allowed access to the contents of the jdk.test/test
+        // package since that package was exported to the transletModule above.
+        for (Future<Void> result : results) {
+            try {
+                result.get();
+                passed++;
+            } catch (Throwable x) {
+                x.printStackTrace();
+                failed++;
+            }
+        }
+
+        System.out.println("passed: " + passed);
+        System.out.println("failed: " + failed);
+    }
+
+    public static void callback() { }
+}

hotspot/test/runtime/modules/ModuleStress/src/jdk.translet/translet/MainGC.java

@@ -0,0 +1,30 @@
+/*
+ * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package translet;
+
+public class MainGC {
+    public static void go() {
+        test.MainGC.callback();
+    }
+}

jaxp/.hgtags

@@ -369,3 +369,4 @@ f8899b1884e2c4a000dbcc5b1a80954245fe462e jdk-9+122
 e04a15153cc293f05fcd60bc98236f50e16af46a jdk-9+124
 493eb91ec32a6dea7604cfbd86c10045ad9af15b jdk-9+125
 15722f71281f034bc696d8b96136da2ef34da44f jdk-9+126
+bdc3c0b737efbf899709eb3121ce760dcfb51151 jdk-9+127

jaxws/.hgtags

@@ -372,3 +372,4 @@ c42decd28bbfa817347112ed6053b5fbd30517a2 jdk-9+123
 1600da1665cd2cc127014e8c002b328ec33a9147 jdk-9+124
 5b0570e3db29f6b8c80a4beac70d51284507b203 jdk-9+125
 264a44128cd6286e598d5a849ceeb613c06269d0 jdk-9+126
+06d706c70634775418dc79a2671780ba1c624fd2 jdk-9+127

jdk/src/java.base/share/classes/com/sun/security/ntlm/NTLM.java

@@ -169,7 +169,7 @@ class NTLM {
 
         byte[] readSecurityBuffer(int offset) throws NTLMException {
             int pos = readInt(offset+4);
-            if (pos == 0) return null;
+            if (pos == 0) return new byte[0];
             try {
                 return Arrays.copyOfRange(
                         internal, pos, pos + readShort(offset));

jdk/src/java.base/share/classes/java/lang/Math.java

@@ -1613,6 +1613,8 @@ public final class Math {
      * @return (<i>a</i>&nbsp;&times;&nbsp;<i>b</i>&nbsp;+&nbsp;<i>c</i>)
      * computed, as if with unlimited range and precision, and rounded
      * once to the nearest {@code double} value
+     *
+     * @since 9
      */
     // @HotSpotIntrinsicCandidate
     public static double fma(double a, double b, double c) {
@@ -1728,6 +1730,8 @@ public final class Math {
      * @return (<i>a</i>&nbsp;&times;&nbsp;<i>b</i>&nbsp;+&nbsp;<i>c</i>)
      * computed, as if with unlimited range and precision, and rounded
      * once to the nearest {@code float} value
+     *
+     * @since 9
      */
     // @HotSpotIntrinsicCandidate
     public static float fma(float a, float b, float c) {

jdk/src/java.base/share/classes/java/lang/StrictMath.java

@@ -1276,6 +1276,8 @@ public final class StrictMath {
      * @return (<i>a</i>&nbsp;&times;&nbsp;<i>b</i>&nbsp;+&nbsp;<i>c</i>)
      * computed, as if with unlimited range and precision, and rounded
      * once to the nearest {@code double} value
+     *
+     * @since 9
      */
     public static double fma(double a, double b, double c) {
         return Math.fma(a, b, c);
@@ -1328,6 +1330,8 @@ public final class StrictMath {
      * @return (<i>a</i>&nbsp;&times;&nbsp;<i>b</i>&nbsp;+&nbsp;<i>c</i>)
      * computed, as if with unlimited range and precision, and rounded
      * once to the nearest {@code float} value
+     *
+     * @since 9
      */
     public static float fma(float a, float b, float c) {
         return Math.fma(a, b, c);

jdk/src/java.base/share/classes/java/lang/module/package-info.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013, 2016 Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2013, 2016, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it

jdk/src/java.base/share/classes/java/nio/file/Files.java

@@ -3290,8 +3290,8 @@ public final class Files {
      * a size of {@code 0}. All bytes in the byte array are written to the file.
      * The method ensures that the file is closed when all bytes have been
      * written (or an I/O error or other runtime exception is thrown). If an I/O
-     * error occurs then it may do so after the file has created or truncated,
-     * or after some bytes have been written to the file.
+     * error occurs then it may do so after the file has been created or
+     * truncated, or after some bytes have been written to the file.
      *
      * <p> <b>Usage example</b>: By default the method creates a new file or
      * overwrites an existing file. Suppose you instead want to append bytes
@@ -3360,7 +3360,8 @@ public final class Files {
      * a size of {@code 0}. The method ensures that the file is closed when all
      * lines have been written (or an I/O error or other runtime exception is
      * thrown). If an I/O error occurs then it may do so after the file has
-     * created or truncated, or after some bytes have been written to the file.
+     * been created or truncated, or after some bytes have been written to the
+     * file.
      *
      * @param   path
      *          the path to the file

jdk/src/java.base/share/classes/java/util/Queue.java

@@ -124,7 +124,6 @@ package java.util;
  * always well-defined for queues with the same elements but different
  * ordering properties.
  *
- *
  * <p>This interface is a member of the
  * <a href="{@docRoot}/../technotes/guides/collections/index.html">
  * Java Collections Framework</a>.

jdk/src/java.base/share/classes/java/util/concurrent/ConcurrentHashMap.java

@@ -68,6 +68,7 @@ import java.util.function.ToIntFunction;
 import java.util.function.ToLongBiFunction;
 import java.util.function.ToLongFunction;
 import java.util.stream.Stream;
+import jdk.internal.misc.Unsafe;
 
 /**
  * A hash table supporting full concurrency of retrievals and
@@ -747,7 +748,7 @@ public class ConcurrentHashMap<K,V> extends AbstractMap<K,V>
     /* ---------------- Table element access -------------- */
 
     /*
-     * Volatile access methods are used for table elements as well as
+     * Atomic access methods are used for table elements as well as
      * elements of in-progress next table while resizing.  All uses of
      * the tab arguments must be null checked by callers.  All callers
      * also paranoically precheck that tab's length is not zero (or an
@@ -757,14 +758,12 @@ public class ConcurrentHashMap<K,V> extends AbstractMap<K,V>
      * errors by users, these checks must operate on local variables,
      * which accounts for some odd-looking inline assignments below.
      * Note that calls to setTabAt always occur within locked regions,
-     * and so in principle require only release ordering, not
-     * full volatile semantics, but are currently coded as volatile
-     * writes to be conservative.
+     * and so require only release ordering.
      */
 
     @SuppressWarnings("unchecked")
     static final <K,V> Node<K,V> tabAt(Node<K,V>[] tab, int i) {
-        return (Node<K,V>)U.getObjectVolatile(tab, ((long)i << ASHIFT) + ABASE);
+        return (Node<K,V>)U.getObjectAcquire(tab, ((long)i << ASHIFT) + ABASE);
     }
 
     static final <K,V> boolean casTabAt(Node<K,V>[] tab, int i,
@@ -773,7 +772,7 @@ public class ConcurrentHashMap<K,V> extends AbstractMap<K,V>
     }
 
     static final <K,V> void setTabAt(Node<K,V>[] tab, int i, Node<K,V> v) {
-        U.putObjectVolatile(tab, ((long)i << ASHIFT) + ABASE, v);
+        U.putObjectRelease(tab, ((long)i << ASHIFT) + ABASE, v);
     }
 
     /* ---------------- Fields -------------- */
@@ -3298,7 +3297,7 @@ public class ConcurrentHashMap<K,V> extends AbstractMap<K,V>
             return true;
         }
 
-        private static final jdk.internal.misc.Unsafe U = jdk.internal.misc.Unsafe.getUnsafe();
+        private static final Unsafe U = Unsafe.getUnsafe();
         private static final long LOCKSTATE;
         static {
             try {
@@ -6341,7 +6340,7 @@ public class ConcurrentHashMap<K,V> extends AbstractMap<K,V>
     }
 
     // Unsafe mechanics
-    private static final jdk.internal.misc.Unsafe U = jdk.internal.misc.Unsafe.getUnsafe();
+    private static final Unsafe U = Unsafe.getUnsafe();
     private static final long SIZECTL;
     private static final long TRANSFERINDEX;
     private static final long BASECOUNT;

jdk/src/java.base/share/classes/java/util/concurrent/ConcurrentLinkedDeque.java

@@ -35,6 +35,8 @@
 
 package java.util.concurrent;
 
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.VarHandle;
 import java.util.AbstractCollection;
 import java.util.Arrays;
 import java.util.Collection;
@@ -292,64 +294,23 @@ public class ConcurrentLinkedDeque<E>
         volatile Node<E> prev;
         volatile E item;
         volatile Node<E> next;
+    }
 
-        Node() {  // default constructor for NEXT_TERMINATOR, PREV_TERMINATOR
-        }
-
-        /**
-         * Constructs a new node.  Uses relaxed write because item can
-         * only be seen after publication via casNext or casPrev.
-         */
-        Node(E item) {
-            U.putObject(this, ITEM, item);
-        }
-
-        boolean casItem(E cmp, E val) {
-            return U.compareAndSwapObject(this, ITEM, cmp, val);
-        }
-
-        void lazySetNext(Node<E> val) {
-            U.putObjectRelease(this, NEXT, val);
-        }
-
-        boolean casNext(Node<E> cmp, Node<E> val) {
-            return U.compareAndSwapObject(this, NEXT, cmp, val);
-        }
-
-        void lazySetPrev(Node<E> val) {
-            U.putObjectRelease(this, PREV, val);
-        }
-
-        boolean casPrev(Node<E> cmp, Node<E> val) {
-            return U.compareAndSwapObject(this, PREV, cmp, val);
-        }
-
-        // Unsafe mechanics
-
-        private static final jdk.internal.misc.Unsafe U = jdk.internal.misc.Unsafe.getUnsafe();
-        private static final long PREV;
-        private static final long ITEM;
-        private static final long NEXT;
-
-        static {
-            try {
-                PREV = U.objectFieldOffset
-                    (Node.class.getDeclaredField("prev"));
-                ITEM = U.objectFieldOffset
-                    (Node.class.getDeclaredField("item"));
-                NEXT = U.objectFieldOffset
-                    (Node.class.getDeclaredField("next"));
-            } catch (ReflectiveOperationException e) {
-                throw new Error(e);
-            }
-        }
+    /**
+     * Returns a new node holding item.  Uses relaxed write because item
+     * can only be seen after piggy-backing publication via CAS.
+     */
+    static <E> Node<E> newNode(E item) {
+        Node<E> node = new Node<E>();
+        ITEM.set(node, item);
+        return node;
     }
 
     /**
      * Links e as first element.
      */
     private void linkFirst(E e) {
-        final Node<E> newNode = new Node<E>(Objects.requireNonNull(e));
+        final Node<E> newNode = newNode(Objects.requireNonNull(e));
 
         restartFromHead:
         for (;;)
@@ -363,13 +324,13 @@ public class ConcurrentLinkedDeque<E>
                     continue restartFromHead;
                 else {
                     // p is first node
-                    newNode.lazySetNext(p); // CAS piggyback
-                    if (p.casPrev(null, newNode)) {
+                    NEXT.set(newNode, p); // CAS piggyback
+                    if (PREV.compareAndSet(p, null, newNode)) {
                         // Successful CAS is the linearization point
                         // for e to become an element of this deque,
                         // and for newNode to become "live".
-                        if (p != h) // hop two nodes at a time
-                            casHead(h, newNode);  // Failure is OK.
+                        if (p != h) // hop two nodes at a time; failure is OK
+                            HEAD.weakCompareAndSetVolatile(this, h, newNode);
                         return;
                     }
                     // Lost CAS race to another thread; re-read prev
@@ -381,7 +342,7 @@ public class ConcurrentLinkedDeque<E>
      * Links e as last element.
      */
     private void linkLast(E e) {
-        final Node<E> newNode = new Node<E>(Objects.requireNonNull(e));
+        final Node<E> newNode = newNode(Objects.requireNonNull(e));
 
         restartFromTail:
         for (;;)
@@ -395,13 +356,13 @@ public class ConcurrentLinkedDeque<E>
                     continue restartFromTail;
                 else {
                     // p is last node
-                    newNode.lazySetPrev(p); // CAS piggyback
-                    if (p.casNext(null, newNode)) {
+                    PREV.set(newNode, p); // CAS piggyback
+                    if (NEXT.compareAndSet(p, null, newNode)) {
                         // Successful CAS is the linearization point
                         // for e to become an element of this deque,
                         // and for newNode to become "live".
-                        if (p != t) // hop two nodes at a time
-                            casTail(t, newNode);  // Failure is OK.
+                        if (p != t) // hop two nodes at a time; failure is OK
+                            TAIL.weakCompareAndSetVolatile(this, t, newNode);
                         return;
                     }
                     // Lost CAS race to another thread; re-read next
@@ -516,8 +477,8 @@ public class ConcurrentLinkedDeque<E>
                 updateTail(); // Ensure x is not reachable from tail
 
                 // Finally, actually gc-unlink
-                x.lazySetPrev(isFirst ? prevTerminator() : x);
-                x.lazySetNext(isLast  ? nextTerminator() : x);
+                PREV.setRelease(x, isFirst ? prevTerminator() : x);
+                NEXT.setRelease(x, isLast  ? nextTerminator() : x);
             }
         }
     }
@@ -531,7 +492,8 @@ public class ConcurrentLinkedDeque<E>
         // assert first.item == null;
         for (Node<E> o = null, p = next, q;;) {
             if (p.item != null || (q = p.next) == null) {
-                if (o != null && p.prev != p && first.casNext(next, p)) {
+                if (o != null && p.prev != p &&
+                    NEXT.compareAndSet(first, next, p)) {
                     skipDeletedPredecessors(p);
                     if (first.prev == null &&
                         (p.next == null || p.item != null) &&
@@ -541,8 +503,8 @@ public class ConcurrentLinkedDeque<E>
                         updateTail(); // Ensure o is not reachable from tail
 
                         // Finally, actually gc-unlink
-                        o.lazySetNext(o);
-                        o.lazySetPrev(prevTerminator());
+                        NEXT.setRelease(o, o);
+                        PREV.setRelease(o, prevTerminator());
                     }
                 }
                 return;
@@ -565,7 +527,8 @@ public class ConcurrentLinkedDeque<E>
         // assert last.item == null;
         for (Node<E> o = null, p = prev, q;;) {
             if (p.item != null || (q = p.prev) == null) {
-                if (o != null && p.next != p && last.casPrev(prev, p)) {
+                if (o != null && p.next != p &&
+                    PREV.compareAndSet(last, prev, p)) {
                     skipDeletedSuccessors(p);
                     if (last.next == null &&
                         (p.prev == null || p.item != null) &&
@@ -575,8 +538,8 @@ public class ConcurrentLinkedDeque<E>
                         updateTail(); // Ensure o is not reachable from tail
 
                         // Finally, actually gc-unlink
-                        o.lazySetPrev(o);
-                        o.lazySetNext(nextTerminator());
+                        PREV.setRelease(o, o);
+                        NEXT.setRelease(o, nextTerminator());
                     }
                 }
                 return;
@@ -607,7 +570,7 @@ public class ConcurrentLinkedDeque<E>
                     (q = (p = q).prev) == null) {
                     // It is possible that p is PREV_TERMINATOR,
                     // but if so, the CAS is guaranteed to fail.
-                    if (casHead(h, p))
+                    if (HEAD.compareAndSet(this, h, p))
                         return;
                     else
                         continue restartFromHead;
@@ -637,7 +600,7 @@ public class ConcurrentLinkedDeque<E>
                     (q = (p = q).next) == null) {
                     // It is possible that p is NEXT_TERMINATOR,
                     // but if so, the CAS is guaranteed to fail.
-                    if (casTail(t, p))
+                    if (TAIL.compareAndSet(this, t, p))
                         return;
                     else
                         continue restartFromTail;
@@ -675,7 +638,7 @@ public class ConcurrentLinkedDeque<E>
             }
 
             // found active CAS target
-            if (prev == p || x.casPrev(prev, p))
+            if (prev == p || PREV.compareAndSet(x, prev, p))
                 return;
 
         } while (x.item != null || x.next == null);
@@ -706,7 +669,7 @@ public class ConcurrentLinkedDeque<E>
             }
 
             // found active CAS target
-            if (next == p || x.casNext(next, p))
+            if (next == p || NEXT.compareAndSet(x, next, p))
                 return;
 
         } while (x.item != null || x.prev == null);
@@ -751,7 +714,7 @@ public class ConcurrentLinkedDeque<E>
                 else if (p == h
                          // It is possible that p is PREV_TERMINATOR,
                          // but if so, the CAS is guaranteed to fail.
-                         || casHead(h, p))
+                         || HEAD.compareAndSet(this, h, p))
                     return p;
                 else
                     continue restartFromHead;
@@ -776,7 +739,7 @@ public class ConcurrentLinkedDeque<E>
                 else if (p == t
                          // It is possible that p is NEXT_TERMINATOR,
                          // but if so, the CAS is guaranteed to fail.
-                         || casTail(t, p))
+                         || TAIL.compareAndSet(this, t, p))
                     return p;
                 else
                     continue restartFromTail;
@@ -802,7 +765,7 @@ public class ConcurrentLinkedDeque<E>
      * Constructs an empty deque.
      */
     public ConcurrentLinkedDeque() {
-        head = tail = new Node<E>(null);
+        head = tail = new Node<E>();
     }
 
     /**
@@ -818,12 +781,12 @@ public class ConcurrentLinkedDeque<E>
         // Copy c into a private chain of Nodes
         Node<E> h = null, t = null;
         for (E e : c) {
-            Node<E> newNode = new Node<E>(Objects.requireNonNull(e));
+            Node<E> newNode = newNode(Objects.requireNonNull(e));
             if (h == null)
                 h = t = newNode;
             else {
-                t.lazySetNext(newNode);
-                newNode.lazySetPrev(t);
+                NEXT.set(t, newNode);
+                PREV.set(newNode, t);
                 t = newNode;
             }
         }
@@ -836,12 +799,12 @@ public class ConcurrentLinkedDeque<E>
     private void initHeadTail(Node<E> h, Node<E> t) {
         if (h == t) {
             if (h == null)
-                h = t = new Node<E>(null);
+                h = t = new Node<E>();
             else {
                 // Avoid edge case of a single Node with non-null item.
-                Node<E> newNode = new Node<E>(null);
-                t.lazySetNext(newNode);
-                newNode.lazySetPrev(t);
+                Node<E> newNode = new Node<E>();
+                NEXT.set(t, newNode);
+                PREV.set(newNode, t);
                 t = newNode;
             }
         }
@@ -934,7 +897,7 @@ public class ConcurrentLinkedDeque<E>
     public E pollFirst() {
         for (Node<E> p = first(); p != null; p = succ(p)) {
             E item = p.item;
-            if (item != null && p.casItem(item, null)) {
+            if (item != null && ITEM.compareAndSet(p, item, null)) {
                 unlink(p);
                 return item;
             }
@@ -945,7 +908,7 @@ public class ConcurrentLinkedDeque<E>
     public E pollLast() {
         for (Node<E> p = last(); p != null; p = pred(p)) {
             E item = p.item;
-            if (item != null && p.casItem(item, null)) {
+            if (item != null && ITEM.compareAndSet(p, item, null)) {
                 unlink(p);
                 return item;
             }
@@ -1031,7 +994,8 @@ public class ConcurrentLinkedDeque<E>
         Objects.requireNonNull(o);
         for (Node<E> p = first(); p != null; p = succ(p)) {
             E item = p.item;
-            if (item != null && o.equals(item) && p.casItem(item, null)) {
+            if (item != null && o.equals(item) &&
+                ITEM.compareAndSet(p, item, null)) {
                 unlink(p);
                 return true;
             }
@@ -1055,7 +1019,8 @@ public class ConcurrentLinkedDeque<E>
         Objects.requireNonNull(o);
         for (Node<E> p = last(); p != null; p = pred(p)) {
             E item = p.item;
-            if (item != null && o.equals(item) && p.casItem(item, null)) {
+            if (item != null && o.equals(item) &&
+                ITEM.compareAndSet(p, item, null)) {
                 unlink(p);
                 return true;
             }
@@ -1159,12 +1124,12 @@ public class ConcurrentLinkedDeque<E>
         // Copy c into a private chain of Nodes
         Node<E> beginningOfTheEnd = null, last = null;
         for (E e : c) {
-            Node<E> newNode = new Node<E>(Objects.requireNonNull(e));
+            Node<E> newNode = newNode(Objects.requireNonNull(e));
             if (beginningOfTheEnd == null)
                 beginningOfTheEnd = last = newNode;
             else {
-                last.lazySetNext(newNode);
-                newNode.lazySetPrev(last);
+                NEXT.set(last, newNode);
+                PREV.set(newNode, last);
                 last = newNode;
             }
         }
@@ -1184,16 +1149,16 @@ public class ConcurrentLinkedDeque<E>
                     continue restartFromTail;
                 else {
                     // p is last node
-                    beginningOfTheEnd.lazySetPrev(p); // CAS piggyback
-                    if (p.casNext(null, beginningOfTheEnd)) {
+                    PREV.set(beginningOfTheEnd, p); // CAS piggyback
+                    if (NEXT.compareAndSet(p, null, beginningOfTheEnd)) {
                         // Successful CAS is the linearization point
                         // for all elements to be added to this deque.
-                        if (!casTail(t, last)) {
+                        if (!TAIL.weakCompareAndSetVolatile(this, t, last)) {
                             // Try a little harder to update tail,
                             // since we may be adding many elements.
                             t = tail;
                             if (last.next == null)
-                                casTail(t, last);
+                                TAIL.weakCompareAndSetVolatile(this, t, last);
                         }
                         return true;
                     }
@@ -1586,41 +1551,38 @@ public class ConcurrentLinkedDeque<E>
         Node<E> h = null, t = null;
         for (Object item; (item = s.readObject()) != null; ) {
             @SuppressWarnings("unchecked")
-            Node<E> newNode = new Node<E>((E) item);
+            Node<E> newNode = newNode((E) item);
             if (h == null)
                 h = t = newNode;
             else {
-                t.lazySetNext(newNode);
-                newNode.lazySetPrev(t);
+                NEXT.set(t, newNode);
+                PREV.set(newNode, t);
                 t = newNode;
             }
         }
         initHeadTail(h, t);
     }
 
-    private boolean casHead(Node<E> cmp, Node<E> val) {
-        return U.compareAndSwapObject(this, HEAD, cmp, val);
-    }
-
-    private boolean casTail(Node<E> cmp, Node<E> val) {
-        return U.compareAndSwapObject(this, TAIL, cmp, val);
-    }
-
-    // Unsafe mechanics
-
-    private static final jdk.internal.misc.Unsafe U = jdk.internal.misc.Unsafe.getUnsafe();
-    private static final long HEAD;
-    private static final long TAIL;
+    // VarHandle mechanics
+    private static final VarHandle HEAD;
+    private static final VarHandle TAIL;
+    private static final VarHandle PREV;
+    private static final VarHandle NEXT;
+    private static final VarHandle ITEM;
     static {
         PREV_TERMINATOR = new Node<Object>();
         PREV_TERMINATOR.next = PREV_TERMINATOR;
         NEXT_TERMINATOR = new Node<Object>();
         NEXT_TERMINATOR.prev = NEXT_TERMINATOR;
         try {
-            HEAD = U.objectFieldOffset
-                (ConcurrentLinkedDeque.class.getDeclaredField("head"));
-            TAIL = U.objectFieldOffset
-                (ConcurrentLinkedDeque.class.getDeclaredField("tail"));
+            MethodHandles.Lookup l = MethodHandles.lookup();
+            HEAD = l.findVarHandle(ConcurrentLinkedDeque.class, "head",
+                                   Node.class);
+            TAIL = l.findVarHandle(ConcurrentLinkedDeque.class, "tail",
+                                   Node.class);
+            PREV = l.findVarHandle(Node.class, "prev", Node.class);
+            NEXT = l.findVarHandle(Node.class, "next", Node.class);
+            ITEM = l.findVarHandle(Node.class, "item", Object.class);
         } catch (ReflectiveOperationException e) {
             throw new Error(e);
         }

jdk/src/java.base/share/classes/java/util/concurrent/ConcurrentLinkedQueue.java

@@ -35,6 +35,8 @@
 
 package java.util.concurrent;
 
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.VarHandle;
 import java.util.AbstractQueue;
 import java.util.Arrays;
 import java.util.Collection;
@@ -166,9 +168,8 @@ public class ConcurrentLinkedQueue<E> extends AbstractQueue<E>
      * this is merely an optimization.
      *
      * When constructing a Node (before enqueuing it) we avoid paying
-     * for a volatile write to item by using Unsafe.putObject instead
-     * of a normal write.  This allows the cost of enqueue to be
-     * "one-and-a-half" CASes.
+     * for a volatile write to item.  This allows the cost of enqueue
+     * to be "one-and-a-half" CASes.
      *
      * Both head and tail may or may not point to a Node with a
      * non-null item.  If the queue is empty, all items must of course
@@ -178,33 +179,21 @@ public class ConcurrentLinkedQueue<E> extends AbstractQueue<E>
      * optimization.
      */
 
-    private static class Node<E> {
+    static final class Node<E> {
         volatile E item;
         volatile Node<E> next;
     }
 
     /**
      * Returns a new node holding item.  Uses relaxed write because item
-     * can only be seen after piggy-backing publication via casNext.
+     * can only be seen after piggy-backing publication via CAS.
      */
     static <E> Node<E> newNode(E item) {
         Node<E> node = new Node<E>();
-        U.putObject(node, ITEM, item);
+        ITEM.set(node, item);
         return node;
     }
 
-    static <E> boolean casItem(Node<E> node, E cmp, E val) {
-        return U.compareAndSwapObject(node, ITEM, cmp, val);
-    }
-
-    static <E> void lazySetNext(Node<E> node, Node<E> val) {
-        U.putObjectRelease(node, NEXT, val);
-    }
-
-    static <E> boolean casNext(Node<E> node, Node<E> cmp, Node<E> val) {
-        return U.compareAndSwapObject(node, NEXT, cmp, val);
-    }
-
     /**
      * A node from which the first live (non-deleted) node (if any)
      * can be reached in O(1) time.
@@ -256,7 +245,7 @@ public class ConcurrentLinkedQueue<E> extends AbstractQueue<E>
             if (h == null)
                 h = t = newNode;
             else {
-                lazySetNext(t, newNode);
+                NEXT.set(t, newNode);
                 t = newNode;
             }
         }
@@ -286,8 +275,8 @@ public class ConcurrentLinkedQueue<E> extends AbstractQueue<E>
      */
     final void updateHead(Node<E> h, Node<E> p) {
         // assert h != null && p != null && (h == p || h.item == null);
-        if (h != p && casHead(h, p))
-            lazySetNext(h, h);
+        if (h != p && HEAD.compareAndSet(this, h, p))
+            NEXT.setRelease(h, h);
     }
 
     /**
@@ -314,12 +303,12 @@ public class ConcurrentLinkedQueue<E> extends AbstractQueue<E>
             Node<E> q = p.next;
             if (q == null) {
                 // p is last node
-                if (casNext(p, null, newNode)) {
+                if (NEXT.compareAndSet(p, null, newNode)) {
                     // Successful CAS is the linearization point
                     // for e to become an element of this queue,
                     // and for newNode to become "live".
-                    if (p != t) // hop two nodes at a time
-                        casTail(t, newNode);  // Failure is OK.
+                    if (p != t) // hop two nodes at a time; failure is OK
+                        TAIL.weakCompareAndSetVolatile(this, t, newNode);
                     return true;
                 }
                 // Lost CAS race to another thread; re-read next
@@ -342,7 +331,7 @@ public class ConcurrentLinkedQueue<E> extends AbstractQueue<E>
             for (Node<E> h = head, p = h, q;;) {
                 E item = p.item;
 
-                if (item != null && casItem(p, item, null)) {
+                if (item != null && ITEM.compareAndSet(p, item, null)) {
                     // Successful CAS is the linearization point
                     // for item to be removed from this queue.
                     if (p != h) // hop two nodes at a time
@@ -483,12 +472,12 @@ public class ConcurrentLinkedQueue<E> extends AbstractQueue<E>
                         next = succ(p);
                         continue;
                     }
-                    removed = casItem(p, item, null);
+                    removed = ITEM.compareAndSet(p, item, null);
                 }
 
                 next = succ(p);
                 if (pred != null && next != null) // unlink
-                    casNext(pred, p, next);
+                    NEXT.weakCompareAndSetVolatile(pred, p, next);
                 if (removed)
                     return true;
             }
@@ -520,7 +509,7 @@ public class ConcurrentLinkedQueue<E> extends AbstractQueue<E>
             if (beginningOfTheEnd == null)
                 beginningOfTheEnd = last = newNode;
             else {
-                lazySetNext(last, newNode);
+                NEXT.set(last, newNode);
                 last = newNode;
             }
         }
@@ -532,15 +521,15 @@ public class ConcurrentLinkedQueue<E> extends AbstractQueue<E>
             Node<E> q = p.next;
             if (q == null) {
                 // p is last node
-                if (casNext(p, null, beginningOfTheEnd)) {
+                if (NEXT.compareAndSet(p, null, beginningOfTheEnd)) {
                     // Successful CAS is the linearization point
                     // for all elements to be added to this queue.
-                    if (!casTail(t, last)) {
+                    if (!TAIL.weakCompareAndSetVolatile(this, t, last)) {
                         // Try a little harder to update tail,
                         // since we may be adding many elements.
                         t = tail;
                         if (last.next == null)
-                            casTail(t, last);
+                            TAIL.weakCompareAndSetVolatile(this, t, last);
                     }
                     return true;
                 }
@@ -744,7 +733,7 @@ public class ConcurrentLinkedQueue<E> extends AbstractQueue<E>
                 }
                 // unlink deleted nodes
                 if ((q = succ(p)) != null)
-                    casNext(pred, p, q);
+                    NEXT.compareAndSet(pred, p, q);
             }
         }
 
@@ -801,7 +790,7 @@ public class ConcurrentLinkedQueue<E> extends AbstractQueue<E>
             if (h == null)
                 h = t = newNode;
             else {
-                lazySetNext(t, newNode);
+                NEXT.set(t, newNode);
                 t = newNode;
             }
         }
@@ -919,31 +908,20 @@ public class ConcurrentLinkedQueue<E> extends AbstractQueue<E>
         return new CLQSpliterator<E>(this);
     }
 
-    private boolean casTail(Node<E> cmp, Node<E> val) {
-        return U.compareAndSwapObject(this, TAIL, cmp, val);
-    }
-
-    private boolean casHead(Node<E> cmp, Node<E> val) {
-        return U.compareAndSwapObject(this, HEAD, cmp, val);
-    }
-
-    // Unsafe mechanics
-
-    private static final jdk.internal.misc.Unsafe U = jdk.internal.misc.Unsafe.getUnsafe();
-    private static final long HEAD;
-    private static final long TAIL;
-    private static final long ITEM;
-    private static final long NEXT;
+    // VarHandle mechanics
+    private static final VarHandle HEAD;
+    private static final VarHandle TAIL;
+    private static final VarHandle ITEM;
+    private static final VarHandle NEXT;
     static {
         try {
-            HEAD = U.objectFieldOffset
-                (ConcurrentLinkedQueue.class.getDeclaredField("head"));
-            TAIL = U.objectFieldOffset
-                (ConcurrentLinkedQueue.class.getDeclaredField("tail"));
-            ITEM = U.objectFieldOffset
-                (Node.class.getDeclaredField("item"));
-            NEXT = U.objectFieldOffset
-                (Node.class.getDeclaredField("next"));
+            MethodHandles.Lookup l = MethodHandles.lookup();
+            HEAD = l.findVarHandle(ConcurrentLinkedQueue.class, "head",
+                                   Node.class);
+            TAIL = l.findVarHandle(ConcurrentLinkedQueue.class, "tail",
+                                   Node.class);
+            ITEM = l.findVarHandle(Node.class, "item", Object.class);
+            NEXT = l.findVarHandle(Node.class, "next", Node.class);
         } catch (ReflectiveOperationException e) {
             throw new Error(e);
         }

jdk/src/java.base/share/classes/java/util/concurrent/ConcurrentSkipListMap.java

@@ -35,6 +35,8 @@
 
 package java.util.concurrent;
 
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.VarHandle;
 import java.io.Serializable;
 import java.util.AbstractCollection;
 import java.util.AbstractMap;
@@ -401,7 +403,7 @@ public class ConcurrentSkipListMap<K,V> extends AbstractMap<K,V>
      * compareAndSet head node.
      */
     private boolean casHead(HeadIndex<K,V> cmp, HeadIndex<K,V> val) {
-        return U.compareAndSwapObject(this, HEAD, cmp, val);
+        return HEAD.compareAndSet(this, cmp, val);
     }
 
     /* ---------------- Nodes -------------- */
@@ -444,14 +446,14 @@ public class ConcurrentSkipListMap<K,V> extends AbstractMap<K,V>
          * compareAndSet value field.
          */
         boolean casValue(Object cmp, Object val) {
-            return U.compareAndSwapObject(this, VALUE, cmp, val);
+            return VALUE.compareAndSet(this, cmp, val);
         }
 
         /**
          * compareAndSet next field.
          */
         boolean casNext(Node<K,V> cmp, Node<K,V> val) {
-            return U.compareAndSwapObject(this, NEXT, cmp, val);
+            return NEXT.compareAndSet(this, cmp, val);
         }
 
         /**
@@ -532,20 +534,16 @@ public class ConcurrentSkipListMap<K,V> extends AbstractMap<K,V>
             return new AbstractMap.SimpleImmutableEntry<K,V>(key, vv);
         }
 
-        // Unsafe mechanics
-
-        private static final jdk.internal.misc.Unsafe U = jdk.internal.misc.Unsafe.getUnsafe();
-        private static final long VALUE;
-        private static final long NEXT;
-
+        // VarHandle mechanics
+        private static final VarHandle VALUE;
+        private static final VarHandle NEXT;
         static {
             try {
-                VALUE = U.objectFieldOffset
-                    (Node.class.getDeclaredField("value"));
-                NEXT = U.objectFieldOffset
-                    (Node.class.getDeclaredField("next"));
+                MethodHandles.Lookup l = MethodHandles.lookup();
+                VALUE = l.findVarHandle(Node.class, "value", Object.class);
+                NEXT = l.findVarHandle(Node.class, "next", Node.class);
             } catch (ReflectiveOperationException e) {
-                throw new Error(e);
+                    throw new Error(e);
             }
         }
     }
@@ -577,7 +575,7 @@ public class ConcurrentSkipListMap<K,V> extends AbstractMap<K,V>
          * compareAndSet right field.
          */
         final boolean casRight(Index<K,V> cmp, Index<K,V> val) {
-            return U.compareAndSwapObject(this, RIGHT, cmp, val);
+            return RIGHT.compareAndSet(this, cmp, val);
         }
 
         /**
@@ -613,13 +611,12 @@ public class ConcurrentSkipListMap<K,V> extends AbstractMap<K,V>
             return node.value != null && casRight(succ, succ.right);
         }
 
-        // Unsafe mechanics
-        private static final jdk.internal.misc.Unsafe U = jdk.internal.misc.Unsafe.getUnsafe();
-        private static final long RIGHT;
+        // VarHandle mechanics
+        private static final VarHandle RIGHT;
         static {
             try {
-                RIGHT = U.objectFieldOffset
-                    (Index.class.getDeclaredField("right"));
+                MethodHandles.Lookup l = MethodHandles.lookup();
+                RIGHT = l.findVarHandle(Index.class, "right", Index.class);
             } catch (ReflectiveOperationException e) {
                 throw new Error(e);
             }
@@ -3607,13 +3604,13 @@ public class ConcurrentSkipListMap<K,V> extends AbstractMap<K,V>
         }
     }
 
-    // Unsafe mechanics
-    private static final jdk.internal.misc.Unsafe U = jdk.internal.misc.Unsafe.getUnsafe();
-    private static final long HEAD;
+    // VarHandle mechanics
+    private static final VarHandle HEAD;
     static {
         try {
-            HEAD = U.objectFieldOffset
-                (ConcurrentSkipListMap.class.getDeclaredField("head"));
+            MethodHandles.Lookup l = MethodHandles.lookup();
+            HEAD = l.findVarHandle(ConcurrentSkipListMap.class, "head",
+                                   HeadIndex.class);
         } catch (ReflectiveOperationException e) {
             throw new Error(e);
         }

jdk/src/java.base/share/classes/java/util/concurrent/ConcurrentSkipListSet.java

@@ -35,6 +35,8 @@
 
 package java.util.concurrent;
 
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.VarHandle;
 import java.util.AbstractSet;
 import java.util.Collection;
 import java.util.Collections;
@@ -507,15 +509,16 @@ public class ConcurrentSkipListSet<E>
 
     // Support for resetting map in clone
     private void setMap(ConcurrentNavigableMap<E,Object> map) {
-        U.putObjectVolatile(this, MAP, map);
+        MAP.setVolatile(this, map);
     }
 
-    private static final jdk.internal.misc.Unsafe U = jdk.internal.misc.Unsafe.getUnsafe();
-    private static final long MAP;
+    // VarHandle mechanics
+    private static final VarHandle MAP;
     static {
         try {
-            MAP = U.objectFieldOffset
-                (ConcurrentSkipListSet.class.getDeclaredField("m"));
+            MethodHandles.Lookup l = MethodHandles.lookup();
+            MAP = l.findVarHandle(ConcurrentSkipListSet.class, "m",
+                                  ConcurrentNavigableMap.class);
         } catch (ReflectiveOperationException e) {
             throw new Error(e);
         }

jdk/src/java.base/share/classes/java/util/concurrent/CopyOnWriteArrayList.java

@@ -34,6 +34,7 @@
 
 package java.util.concurrent;
 
+import java.lang.reflect.Field;
 import java.util.AbstractList;
 import java.util.Arrays;
 import java.util.Collection;
@@ -1541,17 +1542,21 @@ public class CopyOnWriteArrayList<E>
         }
     }
 
-    // Support for resetting lock while deserializing
+    /** Initializes the lock; for use when deserializing or cloning. */
     private void resetLock() {
-        U.putObjectVolatile(this, LOCK, new Object());
-    }
-    private static final jdk.internal.misc.Unsafe U = jdk.internal.misc.Unsafe.getUnsafe();
-    private static final long LOCK;
-    static {
+        Field lockField = java.security.AccessController.doPrivileged(
+            (java.security.PrivilegedAction<Field>) () -> {
+                try {
+                    Field f = CopyOnWriteArrayList.class
+                        .getDeclaredField("lock");
+                    f.setAccessible(true);
+                    return f;
+                } catch (ReflectiveOperationException e) {
+                    throw new Error(e);
+                }});
         try {
-            LOCK = U.objectFieldOffset
-                (CopyOnWriteArrayList.class.getDeclaredField("lock"));
-        } catch (ReflectiveOperationException e) {
+            lockField.set(this, new Object());
+        } catch (IllegalAccessException e) {
             throw new Error(e);
         }
     }

jdk/src/java.base/share/classes/java/util/concurrent/CountedCompleter.java

@@ -35,6 +35,9 @@
 
 package java.util.concurrent;
 
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.VarHandle;
+
 /**
  * A {@link ForkJoinTask} with a completion action performed when
  * triggered and there are no remaining pending actions.
@@ -524,7 +527,7 @@ public abstract class CountedCompleter<T> extends ForkJoinTask<T> {
      * @param delta the value to add
      */
     public final void addToPendingCount(int delta) {
-        U.getAndAddInt(this, PENDING, delta);
+        PENDING.getAndAdd(this, delta);
     }
 
     /**
@@ -536,7 +539,7 @@ public abstract class CountedCompleter<T> extends ForkJoinTask<T> {
      * @return {@code true} if successful
      */
     public final boolean compareAndSetPendingCount(int expected, int count) {
-        return U.compareAndSwapInt(this, PENDING, expected, count);
+        return PENDING.compareAndSet(this, expected, count);
     }
 
     /**
@@ -548,7 +551,7 @@ public abstract class CountedCompleter<T> extends ForkJoinTask<T> {
     public final int decrementPendingCountUnlessZero() {
         int c;
         do {} while ((c = pending) != 0 &&
-                     !U.compareAndSwapInt(this, PENDING, c, c - 1));
+                     !PENDING.weakCompareAndSetVolatile(this, c, c - 1));
         return c;
     }
 
@@ -581,7 +584,7 @@ public abstract class CountedCompleter<T> extends ForkJoinTask<T> {
                     return;
                 }
             }
-            else if (U.compareAndSwapInt(a, PENDING, c, c - 1))
+            else if (PENDING.weakCompareAndSetVolatile(a, c, c - 1))
                 return;
         }
     }
@@ -604,7 +607,7 @@ public abstract class CountedCompleter<T> extends ForkJoinTask<T> {
                     return;
                 }
             }
-            else if (U.compareAndSwapInt(a, PENDING, c, c - 1))
+            else if (PENDING.weakCompareAndSetVolatile(a, c, c - 1))
                 return;
         }
     }
@@ -649,7 +652,7 @@ public abstract class CountedCompleter<T> extends ForkJoinTask<T> {
         for (int c;;) {
             if ((c = pending) == 0)
                 return this;
-            else if (U.compareAndSwapInt(this, PENDING, c, c - 1))
+            else if (PENDING.weakCompareAndSetVolatile(this, c, c - 1))
                 return null;
         }
     }
@@ -753,13 +756,13 @@ public abstract class CountedCompleter<T> extends ForkJoinTask<T> {
      */
     protected void setRawResult(T t) { }
 
-    // Unsafe mechanics
-    private static final jdk.internal.misc.Unsafe U = jdk.internal.misc.Unsafe.getUnsafe();
-    private static final long PENDING;
+    // VarHandle mechanics
+    private static final VarHandle PENDING;
     static {
         try {
-            PENDING = U.objectFieldOffset
-                (CountedCompleter.class.getDeclaredField("pending"));
+            MethodHandles.Lookup l = MethodHandles.lookup();
+            PENDING = l.findVarHandle(CountedCompleter.class, "pending", int.class);
+
         } catch (ReflectiveOperationException e) {
             throw new Error(e);
         }

jdk/src/java.base/share/classes/java/util/concurrent/Exchanger.java

@@ -36,6 +36,10 @@
 
 package java.util.concurrent;
 
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.VarHandle;
+import java.util.concurrent.locks.LockSupport;
+
 /**
  * A synchronization point at which threads can pair and swap elements
  * within pairs.  Each thread presents some object on entry to the
@@ -155,9 +159,7 @@ public class Exchanger<V> {
      * a value that is enough for common platforms.  Additionally,
      * extra care elsewhere is taken to avoid other false/unintended
      * sharing and to enhance locality, including adding padding (via
-     * @Contended) to Nodes, embedding "bound" as an Exchanger field,
-     * and reworking some park/unpark mechanics compared to
-     * LockSupport versions.
+     * @Contended) to Nodes, embedding "bound" as an Exchanger field.
      *
      * The arena starts out with only one used slot. We expand the
      * effective arena size by tracking collisions; i.e., failed CASes
@@ -234,12 +236,12 @@ public class Exchanger<V> {
      * because most of the logic relies on reads of fields that are
      * maintained as local variables so can't be nicely factored --
      * mainly, here, bulky spin->yield->block/cancel code), and
-     * heavily dependent on intrinsics (Unsafe) to use inlined
+     * heavily dependent on intrinsics (VarHandles) to use inlined
      * embedded CAS and related memory access operations (that tend
      * not to be as readily inlined by dynamic compilers when they are
      * hidden behind other methods that would more nicely name and
      * encapsulate the intended effects). This includes the use of
-     * putXRelease to clear fields of the per-thread Nodes between
+     * setRelease to clear fields of the per-thread Nodes between
      * uses. Note that field Node.item is not declared as volatile
      * even though it is read by releasing threads, because they only
      * do so after CAS operations that must precede access, and all
@@ -252,10 +254,10 @@ public class Exchanger<V> {
      */
 
     /**
-     * The byte distance (as a shift value) between any two used slots
-     * in the arena.  1 << ASHIFT should be at least cacheline size.
+     * The index distance (as a shift value) between any two used slots
+     * in the arena, spacing them out to avoid false sharing.
      */
-    private static final int ASHIFT = 7;
+    private static final int ASHIFT = 5;
 
     /**
      * The maximum supported arena index. The maximum allocatable
@@ -356,27 +358,31 @@ public class Exchanger<V> {
      */
     private final Object arenaExchange(Object item, boolean timed, long ns) {
         Node[] a = arena;
+        int alen = a.length;
         Node p = participant.get();
         for (int i = p.index;;) {                      // access slot at i
-            int b, m, c; long j;                       // j is raw array offset
-            Node q = (Node)U.getObjectVolatile(a, j = (i << ASHIFT) + ABASE);
-            if (q != null && U.compareAndSwapObject(a, j, q, null)) {
+            int b, m, c;
+            int j = (i << ASHIFT) + ((1 << ASHIFT) - 1);
+            if (j < 0 || j >= alen)
+                j = alen - 1;
+            Node q = (Node)AA.getAcquire(a, j);
+            if (q != null && AA.compareAndSet(a, j, q, null)) {
                 Object v = q.item;                     // release
                 q.match = item;
                 Thread w = q.parked;
                 if (w != null)
-                    U.unpark(w);
+                    LockSupport.unpark(w);
                 return v;
             }
             else if (i <= (m = (b = bound) & MMASK) && q == null) {
                 p.item = item;                         // offer
-                if (U.compareAndSwapObject(a, j, null, p)) {
+                if (AA.compareAndSet(a, j, null, p)) {
                     long end = (timed && m == 0) ? System.nanoTime() + ns : 0L;
                     Thread t = Thread.currentThread(); // wait
                     for (int h = p.hash, spins = SPINS;;) {
                         Object v = p.match;
                         if (v != null) {
-                            U.putObjectRelease(p, MATCH, null);
+                            MATCH.setRelease(p, null);
                             p.item = null;             // clear for next use
                             p.hash = h;
                             return v;
@@ -389,22 +395,24 @@ public class Exchanger<V> {
                                      (--spins & ((SPINS >>> 1) - 1)) == 0)
                                 Thread.yield();        // two yields per wait
                         }
-                        else if (U.getObjectVolatile(a, j) != p)
+                        else if (AA.getAcquire(a, j) != p)
                             spins = SPINS;       // releaser hasn't set match yet
                         else if (!t.isInterrupted() && m == 0 &&
                                  (!timed ||
                                   (ns = end - System.nanoTime()) > 0L)) {
-                            U.putObject(t, BLOCKER, this); // emulate LockSupport
                             p.parked = t;              // minimize window
-                            if (U.getObjectVolatile(a, j) == p)
-                                U.park(false, ns);
+                            if (AA.getAcquire(a, j) == p) {
+                                if (ns == 0L)
+                                    LockSupport.park(this);
+                                else
+                                    LockSupport.parkNanos(this, ns);
+                            }
                             p.parked = null;
-                            U.putObject(t, BLOCKER, null);
                         }
-                        else if (U.getObjectVolatile(a, j) == p &&
-                                 U.compareAndSwapObject(a, j, p, null)) {
+                        else if (AA.getAcquire(a, j) == p &&
+                                 AA.compareAndSet(a, j, p, null)) {
                             if (m != 0)                // try to shrink
-                                U.compareAndSwapInt(this, BOUND, b, b + SEQ - 1);
+                                BOUND.compareAndSet(this, b, b + SEQ - 1);
                             p.item = null;
                             p.hash = h;
                             i = p.index >>>= 1;        // descend
@@ -426,7 +434,7 @@ public class Exchanger<V> {
                     i = (i != m || m == 0) ? m : m - 1;
                 }
                 else if ((c = p.collides) < m || m == FULL ||
-                         !U.compareAndSwapInt(this, BOUND, b, b + SEQ + 1)) {
+                         !BOUND.compareAndSet(this, b, b + SEQ + 1)) {
                     p.collides = c + 1;
                     i = (i == 0) ? m : i - 1;          // cyclically traverse
                 }
@@ -455,24 +463,24 @@ public class Exchanger<V> {
 
         for (Node q;;) {
             if ((q = slot) != null) {
-                if (U.compareAndSwapObject(this, SLOT, q, null)) {
+                if (SLOT.compareAndSet(this, q, null)) {
                     Object v = q.item;
                     q.match = item;
                     Thread w = q.parked;
                     if (w != null)
-                        U.unpark(w);
+                        LockSupport.unpark(w);
                     return v;
                 }
                 // create arena on contention, but continue until slot null
                 if (NCPU > 1 && bound == 0 &&
-                    U.compareAndSwapInt(this, BOUND, 0, SEQ))
+                    BOUND.compareAndSet(this, 0, SEQ))
                     arena = new Node[(FULL + 2) << ASHIFT];
             }
             else if (arena != null)
                 return null; // caller must reroute to arenaExchange
             else {
                 p.item = item;
-                if (U.compareAndSwapObject(this, SLOT, null, p))
+                if (SLOT.compareAndSet(this, null, p))
                     break;
                 p.item = null;
             }
@@ -495,19 +503,21 @@ public class Exchanger<V> {
                 spins = SPINS;
             else if (!t.isInterrupted() && arena == null &&
                      (!timed || (ns = end - System.nanoTime()) > 0L)) {
-                U.putObject(t, BLOCKER, this);
                 p.parked = t;
-                if (slot == p)
-                    U.park(false, ns);
+                if (slot == p) {
+                    if (ns == 0L)
+                        LockSupport.park(this);
+                    else
+                        LockSupport.parkNanos(this, ns);
+                }
                 p.parked = null;
-                U.putObject(t, BLOCKER, null);
             }
-            else if (U.compareAndSwapObject(this, SLOT, p, null)) {
+            else if (SLOT.compareAndSet(this, p, null)) {
                 v = timed && ns <= 0L && !t.isInterrupted() ? TIMED_OUT : null;
                 break;
             }
         }
-        U.putObjectRelease(p, MATCH, null);
+        MATCH.setRelease(p, null);
         p.item = null;
         p.hash = h;
         return v;
@@ -556,8 +566,9 @@ public class Exchanger<V> {
     @SuppressWarnings("unchecked")
     public V exchange(V x) throws InterruptedException {
         Object v;
+        Node[] a;
         Object item = (x == null) ? NULL_ITEM : x; // translate null args
-        if ((arena != null ||
+        if (((a = arena) != null ||
              (v = slotExchange(item, false, 0L)) == null) &&
             ((Thread.interrupted() || // disambiguates null return
               (v = arenaExchange(item, false, 0L)) == null)))
@@ -623,31 +634,18 @@ public class Exchanger<V> {
         return (v == NULL_ITEM) ? null : (V)v;
     }
 
-    // Unsafe mechanics
-    private static final jdk.internal.misc.Unsafe U = jdk.internal.misc.Unsafe.getUnsafe();
-    private static final long BOUND;
-    private static final long SLOT;
-    private static final long MATCH;
-    private static final long BLOCKER;
-    private static final int ABASE;
+    // VarHandle mechanics
+    private static final VarHandle BOUND;
+    private static final VarHandle SLOT;
+    private static final VarHandle MATCH;
+    private static final VarHandle AA;
     static {
         try {
-            BOUND = U.objectFieldOffset
-                (Exchanger.class.getDeclaredField("bound"));
-            SLOT = U.objectFieldOffset
-                (Exchanger.class.getDeclaredField("slot"));
-
-            MATCH = U.objectFieldOffset
-                (Node.class.getDeclaredField("match"));
-
-            BLOCKER = U.objectFieldOffset
-                (Thread.class.getDeclaredField("parkBlocker"));
-
-            int scale = U.arrayIndexScale(Node[].class);
-            if ((scale & (scale - 1)) != 0 || scale > (1 << ASHIFT))
-                throw new Error("Unsupported array scale");
-            // ABASE absorbs padding in front of element 0
-            ABASE = U.arrayBaseOffset(Node[].class) + (1 << ASHIFT);
+            MethodHandles.Lookup l = MethodHandles.lookup();
+            BOUND = l.findVarHandle(Exchanger.class, "bound", int.class);
+            SLOT = l.findVarHandle(Exchanger.class, "slot", Node.class);
+            MATCH = l.findVarHandle(Node.class, "match", Object.class);
+            AA = MethodHandles.arrayElementVarHandle(Node[].class);
         } catch (ReflectiveOperationException e) {
             throw new Error(e);
         }

jdk/src/java.base/share/classes/java/util/concurrent/ForkJoinTask.java

@@ -36,6 +36,8 @@
 package java.util.concurrent;
 
 import java.io.Serializable;
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.VarHandle;
 import java.lang.ref.ReferenceQueue;
 import java.lang.ref.WeakReference;
 import java.lang.reflect.Constructor;
@@ -92,7 +94,7 @@ import java.util.concurrent.locks.ReentrantLock;
  * encountering the exception; minimally only the latter.
  *
  * <p>It is possible to define and use ForkJoinTasks that may block,
- * but doing do requires three further considerations: (1) Completion
+ * but doing so requires three further considerations: (1) Completion
  * of few if any <em>other</em> tasks should be dependent on a task
  * that blocks on external synchronization or I/O. Event-style async
  * tasks that are never joined (for example, those subclassing {@link
@@ -259,7 +261,7 @@ public abstract class ForkJoinTask<V> implements Future<V>, Serializable {
         for (int s;;) {
             if ((s = status) < 0)
                 return s;
-            if (U.compareAndSwapInt(this, STATUS, s, s | completion)) {
+            if (STATUS.compareAndSet(this, s, s | completion)) {
                 if ((s >>> 16) != 0)
                     synchronized (this) { notifyAll(); }
                 return completion;
@@ -297,7 +299,7 @@ public abstract class ForkJoinTask<V> implements Future<V>, Serializable {
     final void internalWait(long timeout) {
         int s;
         if ((s = status) >= 0 && // force completer to issue notify
-            U.compareAndSwapInt(this, STATUS, s, s | SIGNAL)) {
+            STATUS.compareAndSet(this, s, s | SIGNAL)) {
             synchronized (this) {
                 if (status >= 0)
                     try { wait(timeout); } catch (InterruptedException ie) { }
@@ -319,7 +321,7 @@ public abstract class ForkJoinTask<V> implements Future<V>, Serializable {
         if (s >= 0 && (s = status) >= 0) {
             boolean interrupted = false;
             do {
-                if (U.compareAndSwapInt(this, STATUS, s, s | SIGNAL)) {
+                if (STATUS.compareAndSet(this, s, s | SIGNAL)) {
                     synchronized (this) {
                         if (status >= 0) {
                             try {
@@ -353,7 +355,7 @@ public abstract class ForkJoinTask<V> implements Future<V>, Serializable {
                   ForkJoinPool.common.tryExternalUnpush(this) ? doExec() :
                   0)) >= 0) {
             while ((s = status) >= 0) {
-                if (U.compareAndSwapInt(this, STATUS, s, s | SIGNAL)) {
+                if (STATUS.compareAndSet(this, s, s | SIGNAL)) {
                     synchronized (this) {
                         if (status >= 0)
                             wait(0L);
@@ -400,22 +402,24 @@ public abstract class ForkJoinTask<V> implements Future<V>, Serializable {
     // Exception table support
 
     /**
-     * Table of exceptions thrown by tasks, to enable reporting by
-     * callers. Because exceptions are rare, we don't directly keep
+     * Hash table of exceptions thrown by tasks, to enable reporting
+     * by callers. Because exceptions are rare, we don't directly keep
      * them with task objects, but instead use a weak ref table.  Note
      * that cancellation exceptions don't appear in the table, but are
      * instead recorded as status values.
      *
-     * Note: These statics are initialized below in static block.
+     * The exception table has a fixed capacity.
      */
-    private static final ExceptionNode[] exceptionTable;
-    private static final ReentrantLock exceptionTableLock;
-    private static final ReferenceQueue<Object> exceptionTableRefQueue;
+    private static final ExceptionNode[] exceptionTable
+        = new ExceptionNode[32];
 
-    /**
-     * Fixed capacity for exceptionTable.
-     */
-    private static final int EXCEPTION_MAP_CAPACITY = 32;
+    /** Lock protecting access to exceptionTable. */
+    private static final ReentrantLock exceptionTableLock
+        = new ReentrantLock();
+
+    /** Reference queue of stale exceptionally completed tasks. */
+    private static final ReferenceQueue<ForkJoinTask<?>> exceptionTableRefQueue
+        = new ReferenceQueue<ForkJoinTask<?>>();
 
     /**
      * Key-value nodes for exception table.  The chained hash table
@@ -435,7 +439,7 @@ public abstract class ForkJoinTask<V> implements Future<V>, Serializable {
         final long thrower;  // use id not ref to avoid weak cycles
         final int hashCode;  // store task hashCode before weak ref disappears
         ExceptionNode(ForkJoinTask<?> task, Throwable ex, ExceptionNode next,
-                      ReferenceQueue<Object> exceptionTableRefQueue) {
+                      ReferenceQueue<ForkJoinTask<?>> exceptionTableRefQueue) {
             super(task, exceptionTableRefQueue);
             this.ex = ex;
             this.next = next;
@@ -599,9 +603,8 @@ public abstract class ForkJoinTask<V> implements Future<V>, Serializable {
     private static void expungeStaleExceptions() {
         for (Object x; (x = exceptionTableRefQueue.poll()) != null;) {
             if (x instanceof ExceptionNode) {
-                int hashCode = ((ExceptionNode)x).hashCode;
                 ExceptionNode[] t = exceptionTable;
-                int i = hashCode & (t.length - 1);
+                int i = ((ExceptionNode)x).hashCode & (t.length - 1);
                 ExceptionNode e = t[i];
                 ExceptionNode pred = null;
                 while (e != null) {
@@ -1031,7 +1034,7 @@ public abstract class ForkJoinTask<V> implements Future<V>, Serializable {
                 while ((s = status) >= 0 &&
                        (ns = deadline - System.nanoTime()) > 0L) {
                     if ((ms = TimeUnit.NANOSECONDS.toMillis(ns)) > 0L &&
-                        U.compareAndSwapInt(this, STATUS, s, s | SIGNAL)) {
+                        STATUS.compareAndSet(this, s, s | SIGNAL)) {
                         synchronized (this) {
                             if (status >= 0)
                                 wait(ms); // OK to throw InterruptedException
@@ -1324,8 +1327,8 @@ public abstract class ForkJoinTask<V> implements Future<V>, Serializable {
      */
     public final short setForkJoinTaskTag(short newValue) {
         for (int s;;) {
-            if (U.compareAndSwapInt(this, STATUS, s = status,
-                                    (s & ~SMASK) | (newValue & SMASK)))
+            if (STATUS.compareAndSet(this, s = status,
+                                     (s & ~SMASK) | (newValue & SMASK)))
                 return (short)s;
         }
     }
@@ -1348,8 +1351,8 @@ public abstract class ForkJoinTask<V> implements Future<V>, Serializable {
         for (int s;;) {
             if ((short)(s = status) != expect)
                 return false;
-            if (U.compareAndSwapInt(this, STATUS, s,
-                                    (s & ~SMASK) | (update & SMASK)))
+            if (STATUS.compareAndSet(this, s,
+                                     (s & ~SMASK) | (update & SMASK)))
                 return true;
         }
     }
@@ -1510,17 +1513,12 @@ public abstract class ForkJoinTask<V> implements Future<V>, Serializable {
             setExceptionalCompletion((Throwable)ex);
     }
 
-    // Unsafe mechanics
-    private static final jdk.internal.misc.Unsafe U = jdk.internal.misc.Unsafe.getUnsafe();
-    private static final long STATUS;
-
+    // VarHandle mechanics
+    private static final VarHandle STATUS;
     static {
-        exceptionTableLock = new ReentrantLock();
-        exceptionTableRefQueue = new ReferenceQueue<Object>();
-        exceptionTable = new ExceptionNode[EXCEPTION_MAP_CAPACITY];
         try {
-            STATUS = U.objectFieldOffset
-                (ForkJoinTask.class.getDeclaredField("status"));
+            MethodHandles.Lookup l = MethodHandles.lookup();
+            STATUS = l.findVarHandle(ForkJoinTask.class, "status", int.class);
         } catch (ReflectiveOperationException e) {
             throw new Error(e);
         }

jdk/src/java.base/share/classes/java/util/concurrent/ForkJoinWorkerThread.java

@@ -66,8 +66,9 @@ public class ForkJoinWorkerThread extends Thread {
      * owning thread.
      *
      * Support for (non-public) subclass InnocuousForkJoinWorkerThread
-     * requires that we break quite a lot of encapsulation (via Unsafe)
-     * both here and in the subclass to access and set Thread fields.
+     * requires that we break quite a lot of encapsulation (via helper
+     * methods in ThreadLocalRandom) both here and in the subclass to
+     * access and set Thread fields.
      */
 
     final ForkJoinPool pool;                // the pool this thread works in
@@ -92,8 +93,8 @@ public class ForkJoinWorkerThread extends Thread {
     ForkJoinWorkerThread(ForkJoinPool pool, ThreadGroup threadGroup,
                          AccessControlContext acc) {
         super(threadGroup, null, "aForkJoinWorkerThread");
-        U.putObjectRelease(this, INHERITEDACCESSCONTROLCONTEXT, acc);
-        eraseThreadLocals(); // clear before registering
+        ThreadLocalRandom.setInheritedAccessControlContext(this, acc);
+        ThreadLocalRandom.eraseThreadLocals(this); // clear before registering
         this.pool = pool;
         this.workQueue = pool.registerWorker(this);
     }
@@ -170,38 +171,12 @@ public class ForkJoinWorkerThread extends Thread {
         }
     }
 
-    /**
-     * Erases ThreadLocals by nulling out Thread maps.
-     */
-    final void eraseThreadLocals() {
-        U.putObject(this, THREADLOCALS, null);
-        U.putObject(this, INHERITABLETHREADLOCALS, null);
-    }
-
     /**
      * Non-public hook method for InnocuousForkJoinWorkerThread.
      */
     void afterTopLevelExec() {
     }
 
-    // Set up to allow setting thread fields in constructor
-    private static final jdk.internal.misc.Unsafe U = jdk.internal.misc.Unsafe.getUnsafe();
-    private static final long THREADLOCALS;
-    private static final long INHERITABLETHREADLOCALS;
-    private static final long INHERITEDACCESSCONTROLCONTEXT;
-    static {
-        try {
-            THREADLOCALS = U.objectFieldOffset
-                (Thread.class.getDeclaredField("threadLocals"));
-            INHERITABLETHREADLOCALS = U.objectFieldOffset
-                (Thread.class.getDeclaredField("inheritableThreadLocals"));
-            INHERITEDACCESSCONTROLCONTEXT = U.objectFieldOffset
-                (Thread.class.getDeclaredField("inheritedAccessControlContext"));
-        } catch (ReflectiveOperationException e) {
-            throw new Error(e);
-        }
-    }
-
     /**
      * A worker thread that has no permissions, is not a member of any
      * user-defined ThreadGroup, and erases all ThreadLocals after
@@ -210,7 +185,7 @@ public class ForkJoinWorkerThread extends Thread {
     static final class InnocuousForkJoinWorkerThread extends ForkJoinWorkerThread {
         /** The ThreadGroup for all InnocuousForkJoinWorkerThreads */
         private static final ThreadGroup innocuousThreadGroup =
-            createThreadGroup();
+            ThreadLocalRandom.createThreadGroup("InnocuousForkJoinWorkerThreadGroup");
 
         /** An AccessControlContext supporting no privileges */
         private static final AccessControlContext INNOCUOUS_ACC =
@@ -225,7 +200,7 @@ public class ForkJoinWorkerThread extends Thread {
 
         @Override // to erase ThreadLocals
         void afterTopLevelExec() {
-            eraseThreadLocals();
+            ThreadLocalRandom.eraseThreadLocals(this);
         }
 
         @Override // to always report system loader
@@ -241,33 +216,5 @@ public class ForkJoinWorkerThread extends Thread {
             throw new SecurityException("setContextClassLoader");
         }
 
-        /**
-         * Returns a new group with the system ThreadGroup (the
-         * topmost, parent-less group) as parent.  Uses Unsafe to
-         * traverse Thread.group and ThreadGroup.parent fields.
-         */
-        private static ThreadGroup createThreadGroup() {
-            try {
-                jdk.internal.misc.Unsafe u = jdk.internal.misc.Unsafe.getUnsafe();
-                long tg = u.objectFieldOffset
-                    (Thread.class.getDeclaredField("group"));
-                long gp = u.objectFieldOffset
-                    (ThreadGroup.class.getDeclaredField("parent"));
-                ThreadGroup group = (ThreadGroup)
-                    u.getObject(Thread.currentThread(), tg);
-                while (group != null) {
-                    ThreadGroup parent = (ThreadGroup)u.getObject(group, gp);
-                    if (parent == null)
-                        return new ThreadGroup(group,
-                                               "InnocuousForkJoinWorkerThreadGroup");
-                    group = parent;
-                }
-            } catch (ReflectiveOperationException e) {
-                throw new Error(e);
-            }
-            // fall through if null as cannot-happen safeguard
-            throw new Error("Cannot create ThreadGroup");
-        }
     }
-
 }

jdk/src/java.base/share/classes/java/util/concurrent/FutureTask.java

@@ -35,6 +35,8 @@
 
 package java.util.concurrent;
 
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.VarHandle;
 import java.util.concurrent.locks.LockSupport;
 
 /**
@@ -69,9 +71,6 @@ public class FutureTask<V> implements RunnableFuture<V> {
      * cancellation races. Sync control in the current design relies
      * on a "state" field updated via CAS to track completion, along
      * with a simple Treiber stack to hold waiting threads.
-     *
-     * Style note: As usual, we bypass overhead of using
-     * AtomicXFieldUpdaters and instead directly use Unsafe intrinsics.
      */
 
     /**
@@ -163,9 +162,8 @@ public class FutureTask<V> implements RunnableFuture<V> {
     }
 
     public boolean cancel(boolean mayInterruptIfRunning) {
-        if (!(state == NEW &&
-              U.compareAndSwapInt(this, STATE, NEW,
-                  mayInterruptIfRunning ? INTERRUPTING : CANCELLED)))
+        if (!(state == NEW && STATE.compareAndSet
+              (this, NEW, mayInterruptIfRunning ? INTERRUPTING : CANCELLED)))
             return false;
         try {    // in case call to interrupt throws exception
             if (mayInterruptIfRunning) {
@@ -174,7 +172,7 @@ public class FutureTask<V> implements RunnableFuture<V> {
                     if (t != null)
                         t.interrupt();
                 } finally { // final state
-                    U.putIntRelease(this, STATE, INTERRUPTED);
+                    STATE.setRelease(this, INTERRUPTED);
                 }
             }
         } finally {
@@ -228,9 +226,9 @@ public class FutureTask<V> implements RunnableFuture<V> {
      * @param v the value
      */
     protected void set(V v) {
-        if (U.compareAndSwapInt(this, STATE, NEW, COMPLETING)) {
+        if (STATE.compareAndSet(this, NEW, COMPLETING)) {
             outcome = v;
-            U.putIntRelease(this, STATE, NORMAL); // final state
+            STATE.setRelease(this, NORMAL); // final state
             finishCompletion();
         }
     }
@@ -246,16 +244,16 @@ public class FutureTask<V> implements RunnableFuture<V> {
      * @param t the cause of failure
      */
     protected void setException(Throwable t) {
-        if (U.compareAndSwapInt(this, STATE, NEW, COMPLETING)) {
+        if (STATE.compareAndSet(this, NEW, COMPLETING)) {
             outcome = t;
-            U.putIntRelease(this, STATE, EXCEPTIONAL); // final state
+            STATE.setRelease(this, EXCEPTIONAL); // final state
             finishCompletion();
         }
     }
 
     public void run() {
         if (state != NEW ||
-            !U.compareAndSwapObject(this, RUNNER, null, Thread.currentThread()))
+            !RUNNER.compareAndSet(this, null, Thread.currentThread()))
             return;
         try {
             Callable<V> c = callable;
@@ -296,7 +294,7 @@ public class FutureTask<V> implements RunnableFuture<V> {
      */
     protected boolean runAndReset() {
         if (state != NEW ||
-            !U.compareAndSwapObject(this, RUNNER, null, Thread.currentThread()))
+            !RUNNER.compareAndSet(this, null, Thread.currentThread()))
             return false;
         boolean ran = false;
         int s = state;
@@ -363,7 +361,7 @@ public class FutureTask<V> implements RunnableFuture<V> {
     private void finishCompletion() {
         // assert state > COMPLETING;
         for (WaitNode q; (q = waiters) != null;) {
-            if (U.compareAndSwapObject(this, WAITERS, q, null)) {
+            if (WAITERS.weakCompareAndSetVolatile(this, q, null)) {
                 for (;;) {
                     Thread t = q.thread;
                     if (t != null) {
@@ -425,8 +423,7 @@ public class FutureTask<V> implements RunnableFuture<V> {
                 q = new WaitNode();
             }
             else if (!queued)
-                queued = U.compareAndSwapObject(this, WAITERS,
-                                                q.next = waiters, q);
+                queued = WAITERS.weakCompareAndSetVolatile(this, q.next = waiters, q);
             else if (timed) {
                 final long parkNanos;
                 if (startTime == 0L) { // first time
@@ -475,7 +472,7 @@ public class FutureTask<V> implements RunnableFuture<V> {
                         if (pred.thread == null) // check for race
                             continue retry;
                     }
-                    else if (!U.compareAndSwapObject(this, WAITERS, q, s))
+                    else if (!WAITERS.compareAndSet(this, q, s))
                         continue retry;
                 }
                 break;
@@ -483,19 +480,16 @@ public class FutureTask<V> implements RunnableFuture<V> {
         }
     }
 
-    // Unsafe mechanics
-    private static final jdk.internal.misc.Unsafe U = jdk.internal.misc.Unsafe.getUnsafe();
-    private static final long STATE;
-    private static final long RUNNER;
-    private static final long WAITERS;
+    // VarHandle mechanics
+    private static final VarHandle STATE;
+    private static final VarHandle RUNNER;
+    private static final VarHandle WAITERS;
     static {
         try {
-            STATE = U.objectFieldOffset
-                (FutureTask.class.getDeclaredField("state"));
-            RUNNER = U.objectFieldOffset
-                (FutureTask.class.getDeclaredField("runner"));
-            WAITERS = U.objectFieldOffset
-                (FutureTask.class.getDeclaredField("waiters"));
+            MethodHandles.Lookup l = MethodHandles.lookup();
+            STATE = l.findVarHandle(FutureTask.class, "state", int.class);
+            RUNNER = l.findVarHandle(FutureTask.class, "runner", Thread.class);
+            WAITERS = l.findVarHandle(FutureTask.class, "waiters", WaitNode.class);
         } catch (ReflectiveOperationException e) {
             throw new Error(e);
         }

jdk/src/java.base/share/classes/java/util/concurrent/LinkedTransferQueue.java

@@ -35,6 +35,8 @@
 
 package java.util.concurrent;
 
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.VarHandle;
 import java.util.AbstractQueue;
 import java.util.Arrays;
 import java.util.Collection;
@@ -444,7 +446,7 @@ public class LinkedTransferQueue<E> extends AbstractQueue<E>
 
     /**
      * Queue nodes. Uses Object, not E, for items to allow forgetting
-     * them after use.  Relies heavily on Unsafe mechanics to minimize
+     * them after use.  Relies heavily on VarHandles to minimize
      * unnecessary ordering constraints: Writes that are intrinsically
      * ordered wrt other accesses or CASes use simple relaxed forms.
      */
@@ -456,12 +458,12 @@ public class LinkedTransferQueue<E> extends AbstractQueue<E>
 
         // CAS methods for fields
         final boolean casNext(Node cmp, Node val) {
-            return U.compareAndSwapObject(this, NEXT, cmp, val);
+            return NEXT.compareAndSet(this, cmp, val);
         }
 
         final boolean casItem(Object cmp, Object val) {
             // assert cmp == null || cmp.getClass() != Node.class;
-            return U.compareAndSwapObject(this, ITEM, cmp, val);
+            return ITEM.compareAndSet(this, cmp, val);
         }
 
         /**
@@ -469,7 +471,7 @@ public class LinkedTransferQueue<E> extends AbstractQueue<E>
          * only be seen after publication via casNext.
          */
         Node(Object item, boolean isData) {
-            U.putObject(this, ITEM, item); // relaxed write
+            ITEM.set(this, item); // relaxed write
             this.isData = isData;
         }
 
@@ -478,7 +480,7 @@ public class LinkedTransferQueue<E> extends AbstractQueue<E>
          * only after CASing head field, so uses relaxed write.
          */
         final void forgetNext() {
-            U.putObject(this, NEXT, this);
+            NEXT.set(this, this);
         }
 
         /**
@@ -491,8 +493,8 @@ public class LinkedTransferQueue<E> extends AbstractQueue<E>
          * else we don't care).
          */
         final void forgetContents() {
-            U.putObject(this, ITEM, this);
-            U.putObject(this, WAITER, null);
+            ITEM.set(this, this);
+            WAITER.set(this, null);
         }
 
         /**
@@ -537,19 +539,16 @@ public class LinkedTransferQueue<E> extends AbstractQueue<E>
 
         private static final long serialVersionUID = -3375979862319811754L;
 
-        // Unsafe mechanics
-        private static final jdk.internal.misc.Unsafe U = jdk.internal.misc.Unsafe.getUnsafe();
-        private static final long ITEM;
-        private static final long NEXT;
-        private static final long WAITER;
+        // VarHandle mechanics
+        private static final VarHandle ITEM;
+        private static final VarHandle NEXT;
+        private static final VarHandle WAITER;
         static {
             try {
-                ITEM = U.objectFieldOffset
-                    (Node.class.getDeclaredField("item"));
-                NEXT = U.objectFieldOffset
-                    (Node.class.getDeclaredField("next"));
-                WAITER = U.objectFieldOffset
-                    (Node.class.getDeclaredField("waiter"));
+                MethodHandles.Lookup l = MethodHandles.lookup();
+                ITEM = l.findVarHandle(Node.class, "item", Object.class);
+                NEXT = l.findVarHandle(Node.class, "next", Node.class);
+                WAITER = l.findVarHandle(Node.class, "waiter", Thread.class);
             } catch (ReflectiveOperationException e) {
                 throw new Error(e);
             }
@@ -567,15 +566,15 @@ public class LinkedTransferQueue<E> extends AbstractQueue<E>
 
     // CAS methods for fields
     private boolean casTail(Node cmp, Node val) {
-        return U.compareAndSwapObject(this, TAIL, cmp, val);
+        return TAIL.compareAndSet(this, cmp, val);
     }
 
     private boolean casHead(Node cmp, Node val) {
-        return U.compareAndSwapObject(this, HEAD, cmp, val);
+        return HEAD.compareAndSet(this, cmp, val);
     }
 
     private boolean casSweepVotes(int cmp, int val) {
-        return U.compareAndSwapInt(this, SWEEPVOTES, cmp, val);
+        return SWEEPVOTES.compareAndSet(this, cmp, val);
     }
 
     /*
@@ -1562,20 +1561,19 @@ public class LinkedTransferQueue<E> extends AbstractQueue<E>
         }
     }
 
-    // Unsafe mechanics
-
-    private static final jdk.internal.misc.Unsafe U = jdk.internal.misc.Unsafe.getUnsafe();
-    private static final long HEAD;
-    private static final long TAIL;
-    private static final long SWEEPVOTES;
+    // VarHandle mechanics
+    private static final VarHandle HEAD;
+    private static final VarHandle TAIL;
+    private static final VarHandle SWEEPVOTES;
     static {
         try {
-            HEAD = U.objectFieldOffset
-                (LinkedTransferQueue.class.getDeclaredField("head"));
-            TAIL = U.objectFieldOffset
-                (LinkedTransferQueue.class.getDeclaredField("tail"));
-            SWEEPVOTES = U.objectFieldOffset
-                (LinkedTransferQueue.class.getDeclaredField("sweepVotes"));
+            MethodHandles.Lookup l = MethodHandles.lookup();
+            HEAD = l.findVarHandle(LinkedTransferQueue.class, "head",
+                                   Node.class);
+            TAIL = l.findVarHandle(LinkedTransferQueue.class, "tail",
+                                   Node.class);
+            SWEEPVOTES = l.findVarHandle(LinkedTransferQueue.class, "sweepVotes",
+                                         int.class);
         } catch (ReflectiveOperationException e) {
             throw new Error(e);
         }

jdk/src/java.base/share/classes/java/util/concurrent/Phaser.java

@@ -35,6 +35,8 @@
 
 package java.util.concurrent;
 
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.VarHandle;
 import java.util.concurrent.atomic.AtomicReference;
 import java.util.concurrent.locks.LockSupport;
 
@@ -221,7 +223,6 @@ import java.util.concurrent.locks.LockSupport;
  *   phaser.arriveAndDeregister();
  * }}</pre>
  *
- *
  * <p>To create a set of {@code n} tasks using a tree of phasers, you
  * could use code of the following form, assuming a Task class with a
  * constructor accepting a {@code Phaser} that it registers with upon
@@ -384,7 +385,7 @@ public class Phaser {
             int unarrived = (counts == EMPTY) ? 0 : (counts & UNARRIVED_MASK);
             if (unarrived <= 0)
                 throw new IllegalStateException(badArrive(s));
-            if (U.compareAndSwapLong(this, STATE, s, s-=adjust)) {
+            if (STATE.compareAndSet(this, s, s-=adjust)) {
                 if (unarrived == 1) {
                     long n = s & PARTIES_MASK;  // base of next state
                     int nextUnarrived = (int)n >>> PARTIES_SHIFT;
@@ -397,12 +398,12 @@ public class Phaser {
                             n |= nextUnarrived;
                         int nextPhase = (phase + 1) & MAX_PHASE;
                         n |= (long)nextPhase << PHASE_SHIFT;
-                        U.compareAndSwapLong(this, STATE, s, n);
+                        STATE.compareAndSet(this, s, n);
                         releaseWaiters(phase);
                     }
                     else if (nextUnarrived == 0) { // propagate deregistration
                         phase = parent.doArrive(ONE_DEREGISTER);
-                        U.compareAndSwapLong(this, STATE, s, s | EMPTY);
+                        STATE.compareAndSet(this, s, s | EMPTY);
                     }
                     else
                         phase = parent.doArrive(ONE_ARRIVAL);
@@ -437,13 +438,13 @@ public class Phaser {
                 if (parent == null || reconcileState() == s) {
                     if (unarrived == 0)             // wait out advance
                         root.internalAwaitAdvance(phase, null);
-                    else if (U.compareAndSwapLong(this, STATE, s, s + adjust))
+                    else if (STATE.compareAndSet(this, s, s + adjust))
                         break;
                 }
             }
             else if (parent == null) {              // 1st root registration
                 long next = ((long)phase << PHASE_SHIFT) | adjust;
-                if (U.compareAndSwapLong(this, STATE, s, next))
+                if (STATE.compareAndSet(this, s, next))
                     break;
             }
             else {
@@ -455,8 +456,8 @@ public class Phaser {
                         // finish registration whenever parent registration
                         // succeeded, even when racing with termination,
                         // since these are part of the same "transaction".
-                        while (!U.compareAndSwapLong
-                               (this, STATE, s,
+                        while (!STATE.weakCompareAndSetVolatile
+                               (this, s,
                                 ((long)phase << PHASE_SHIFT) | adjust)) {
                             s = state;
                             phase = (int)(root.state >>> PHASE_SHIFT);
@@ -487,8 +488,8 @@ public class Phaser {
             // CAS to root phase with current parties, tripping unarrived
             while ((phase = (int)(root.state >>> PHASE_SHIFT)) !=
                    (int)(s >>> PHASE_SHIFT) &&
-                   !U.compareAndSwapLong
-                   (this, STATE, s,
+                   !STATE.weakCompareAndSetVolatile
+                   (this, s,
                     s = (((long)phase << PHASE_SHIFT) |
                          ((phase < 0) ? (s & COUNTS_MASK) :
                           (((p = (int)s >>> PARTIES_SHIFT) == 0) ? EMPTY :
@@ -677,7 +678,7 @@ public class Phaser {
             int unarrived = (counts == EMPTY) ? 0 : (counts & UNARRIVED_MASK);
             if (unarrived <= 0)
                 throw new IllegalStateException(badArrive(s));
-            if (U.compareAndSwapLong(this, STATE, s, s -= ONE_ARRIVAL)) {
+            if (STATE.compareAndSet(this, s, s -= ONE_ARRIVAL)) {
                 if (unarrived > 1)
                     return root.internalAwaitAdvance(phase, null);
                 if (root != this)
@@ -692,7 +693,7 @@ public class Phaser {
                     n |= nextUnarrived;
                 int nextPhase = (phase + 1) & MAX_PHASE;
                 n |= (long)nextPhase << PHASE_SHIFT;
-                if (!U.compareAndSwapLong(this, STATE, s, n))
+                if (!STATE.compareAndSet(this, s, n))
                     return (int)(state >>> PHASE_SHIFT); // terminated
                 releaseWaiters(phase);
                 return nextPhase;
@@ -808,7 +809,7 @@ public class Phaser {
         final Phaser root = this.root;
         long s;
         while ((s = root.state) >= 0) {
-            if (U.compareAndSwapLong(root, STATE, s, s | TERMINATION_BIT)) {
+            if (STATE.compareAndSet(root, s, s | TERMINATION_BIT)) {
                 // signal all threads
                 releaseWaiters(0); // Waiters on evenQ
                 releaseWaiters(1); // Waiters on oddQ
@@ -1043,6 +1044,8 @@ public class Phaser {
                     node = new QNode(this, phase, false, false, 0L);
                     node.wasInterrupted = interrupted;
                 }
+                else
+                    Thread.onSpinWait();
             }
             else if (node.isReleasable()) // done or aborted
                 break;
@@ -1131,14 +1134,12 @@ public class Phaser {
         }
     }
 
-    // Unsafe mechanics
-
-    private static final jdk.internal.misc.Unsafe U = jdk.internal.misc.Unsafe.getUnsafe();
-    private static final long STATE;
+    // VarHandle mechanics
+    private static final VarHandle STATE;
     static {
         try {
-            STATE = U.objectFieldOffset
-                (Phaser.class.getDeclaredField("state"));
+            MethodHandles.Lookup l = MethodHandles.lookup();
+            STATE = l.findVarHandle(Phaser.class, "state", long.class);
         } catch (ReflectiveOperationException e) {
             throw new Error(e);
         }

jdk/src/java.base/share/classes/java/util/concurrent/PriorityBlockingQueue.java

@@ -35,6 +35,8 @@
 
 package java.util.concurrent;
 
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.VarHandle;
 import java.util.AbstractQueue;
 import java.util.Arrays;
 import java.util.Collection;
@@ -289,7 +291,7 @@ public class PriorityBlockingQueue<E> extends AbstractQueue<E>
         lock.unlock(); // must release and then re-acquire main lock
         Object[] newArray = null;
         if (allocationSpinLock == 0 &&
-            U.compareAndSwapInt(this, ALLOCATIONSPINLOCK, 0, 1)) {
+            ALLOCATIONSPINLOCK.compareAndSet(this, 0, 1)) {
             try {
                 int newCap = oldCap + ((oldCap < 64) ?
                                        (oldCap + 2) : // grow faster if small
@@ -1009,13 +1011,14 @@ public class PriorityBlockingQueue<E> extends AbstractQueue<E>
         return new PBQSpliterator<E>(this, null, 0, -1);
     }
 
-    // Unsafe mechanics
-    private static final jdk.internal.misc.Unsafe U = jdk.internal.misc.Unsafe.getUnsafe();
-    private static final long ALLOCATIONSPINLOCK;
+    // VarHandle mechanics
+    private static final VarHandle ALLOCATIONSPINLOCK;
     static {
         try {
-            ALLOCATIONSPINLOCK = U.objectFieldOffset
-                (PriorityBlockingQueue.class.getDeclaredField("allocationSpinLock"));
+            MethodHandles.Lookup l = MethodHandles.lookup();
+            ALLOCATIONSPINLOCK = l.findVarHandle(PriorityBlockingQueue.class,
+                                                 "allocationSpinLock",
+                                                 int.class);
         } catch (ReflectiveOperationException e) {
             throw new Error(e);
         }

jdk/src/java.base/share/classes/java/util/concurrent/SubmissionPublisher.java

@@ -35,6 +35,8 @@
 
 package java.util.concurrent;
 
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.VarHandle;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.concurrent.locks.LockSupport;
@@ -866,7 +868,7 @@ public class SubmissionPublisher<T> implements Flow.Publisher<T>,
 
     /** Subscriber for method consume */
     private static final class ConsumerSubscriber<T>
-            implements Flow.Subscriber<T> {
+        implements Flow.Subscriber<T> {
         final CompletableFuture<Void> status;
         final Consumer<? super T> consumer;
         Flow.Subscription subscription;
@@ -906,7 +908,7 @@ public class SubmissionPublisher<T> implements Flow.Publisher<T>,
      */
     @SuppressWarnings("serial")
     static final class ConsumerTask<T> extends ForkJoinTask<Void>
-        implements Runnable {
+        implements Runnable, CompletableFuture.AsynchronousCompletionTask {
         final BufferedSubscription<T> consumer;
         ConsumerTask(BufferedSubscription<T> consumer) {
             this.consumer = consumer;
@@ -959,11 +961,9 @@ public class SubmissionPublisher<T> implements Flow.Publisher<T>,
      * Blocking control relies on the "waiter" field. Producers set
      * the field before trying to block, but must then recheck (via
      * offer) before parking. Signalling then just unparks and clears
-     * waiter field. If the producer and consumer are both in the same
-     * ForkJoinPool, or consumers are running in commonPool, the
-     * producer attempts to help run consumer tasks that it forked
-     * before blocking.  To avoid potential cycles, only one level of
-     * helping is currently supported.
+     * waiter field. If the producer and/or consumer are using a
+     * ForkJoinPool, the producer attempts to help run consumer tasks
+     * via ForkJoinPool.helpAsyncBlocker before blocking.
      *
      * This class uses @Contended and heuristic field declaration
      * ordering to reduce false-sharing-based memory contention among
@@ -983,7 +983,6 @@ public class SubmissionPublisher<T> implements Flow.Publisher<T>,
         volatile long demand;              // # unfilled requests
         int maxCapacity;                   // reduced on OOME
         int putStat;                       // offer result for ManagedBlocker
-        int helpDepth;                     // nested helping depth (at most 1)
         volatile int ctl;                  // atomic run state flags
         volatile int head;                 // next position to take
         int tail;                          // next position to put
@@ -1077,7 +1076,7 @@ public class SubmissionPublisher<T> implements Flow.Publisher<T>,
                 alloc = true;
             }
             else {
-                U.fullFence();                   // recheck
+                VarHandle.fullFence();           // recheck
                 int h = head, t = tail, size = t + 1 - h;
                 if (cap >= size) {
                     a[(cap - 1) & t] = item;
@@ -1116,10 +1115,10 @@ public class SubmissionPublisher<T> implements Flow.Publisher<T>,
                         if (a != null && cap > 0) {
                             int mask = cap - 1;
                             for (int j = head; j != t; ++j) {
-                                long k = ((long)(j & mask) << ASHIFT) + ABASE;
-                                Object x = U.getObjectVolatile(a, k);
+                                int k = j & mask;
+                                Object x = QA.getAcquire(a, k);
                                 if (x != null && // races with consumer
-                                    U.compareAndSwapObject(a, k, x, null))
+                                    QA.compareAndSet(a, k, x, null))
                                     newArray[j & newMask] = x;
                             }
                         }
@@ -1136,100 +1135,43 @@ public class SubmissionPublisher<T> implements Flow.Publisher<T>,
          * initial offer return 0.
          */
         final int submit(T item) {
-            int stat; Executor e; ForkJoinWorkerThread w;
-            if ((stat = offer(item)) == 0 && helpDepth == 0 &&
-                ((e = executor) instanceof ForkJoinPool)) {
-                helpDepth = 1;
-                Thread thread = Thread.currentThread();
-                if ((thread instanceof ForkJoinWorkerThread) &&
-                    ((w = (ForkJoinWorkerThread)thread)).getPool() == e)
-                    stat = internalHelpConsume(w.workQueue, item);
-                else if (e == ForkJoinPool.commonPool())
-                    stat = externalHelpConsume
-                        (ForkJoinPool.commonSubmitterQueue(), item);
-                helpDepth = 0;
-            }
-            if (stat == 0 && (stat = offer(item)) == 0) {
+            int stat;
+            if ((stat = offer(item)) == 0) {
                 putItem = item;
                 timeout = 0L;
-                try {
-                    ForkJoinPool.managedBlock(this);
-                } catch (InterruptedException ie) {
-                    timeout = INTERRUPTED;
+                putStat = 0;
+                ForkJoinPool.helpAsyncBlocker(executor, this);
+                if ((stat = putStat) == 0) {
+                    try {
+                        ForkJoinPool.managedBlock(this);
+                    } catch (InterruptedException ie) {
+                        timeout = INTERRUPTED;
+                    }
+                    stat = putStat;
                 }
-                stat = putStat;
                 if (timeout < 0L)
                     Thread.currentThread().interrupt();
             }
             return stat;
         }
 
-        /**
-         * Tries helping for FJ submitter.
-         */
-        private int internalHelpConsume(ForkJoinPool.WorkQueue w, T item) {
-            int stat = 0;
-            if (w != null) {
-                ForkJoinTask<?> t;
-                while ((t = w.peek()) != null && (t instanceof ConsumerTask)) {
-                    if ((stat = offer(item)) != 0 || !w.tryUnpush(t))
-                        break;
-                    ((ConsumerTask<?>)t).consumer.consume();
-                }
-            }
-            return stat;
-        }
-
-        /**
-         * Tries helping for non-FJ submitter.
-         */
-        private int externalHelpConsume(ForkJoinPool.WorkQueue w, T item) {
-            int stat = 0;
-            if (w != null) {
-                ForkJoinTask<?> t;
-                while ((t = w.peek()) != null && (t instanceof ConsumerTask)) {
-                    if ((stat = offer(item)) != 0 || !w.trySharedUnpush(t))
-                        break;
-                    ((ConsumerTask<?>)t).consumer.consume();
-                }
-            }
-            return stat;
-        }
-
         /**
          * Timeout version; similar to submit.
          */
         final int timedOffer(T item, long nanos) {
-            int stat; Executor e;
-            if ((stat = offer(item)) == 0 && helpDepth == 0 &&
-                ((e = executor) instanceof ForkJoinPool)) {
-                Thread thread = Thread.currentThread();
-                if (((thread instanceof ForkJoinWorkerThread) &&
-                     ((ForkJoinWorkerThread)thread).getPool() == e) ||
-                    e == ForkJoinPool.commonPool()) {
-                    helpDepth = 1;
-                    ForkJoinTask<?> t;
-                    long deadline = System.nanoTime() + nanos;
-                    while ((t = ForkJoinTask.peekNextLocalTask()) != null &&
-                           (t instanceof ConsumerTask)) {
-                        if ((stat = offer(item)) != 0 ||
-                            (nanos = deadline - System.nanoTime()) <= 0L ||
-                            !t.tryUnfork())
-                            break;
-                        ((ConsumerTask<?>)t).consumer.consume();
-                    }
-                    helpDepth = 0;
-                }
-            }
-            if (stat == 0 && (stat = offer(item)) == 0 &&
-                (timeout = nanos) > 0L) {
+            int stat;
+            if ((stat = offer(item)) == 0 && (timeout = nanos) > 0L) {
                 putItem = item;
-                try {
-                    ForkJoinPool.managedBlock(this);
-                } catch (InterruptedException ie) {
-                    timeout = INTERRUPTED;
+                putStat = 0;
+                ForkJoinPool.helpAsyncBlocker(executor, this);
+                if ((stat = putStat) == 0) {
+                    try {
+                        ForkJoinPool.managedBlock(this);
+                    } catch (InterruptedException ie) {
+                        timeout = INTERRUPTED;
+                    }
+                    stat = putStat;
                 }
-                stat = putStat;
                 if (timeout < 0L)
                     Thread.currentThread().interrupt();
             }
@@ -1249,22 +1191,20 @@ public class SubmissionPublisher<T> implements Flow.Publisher<T>,
                 }
                 else if ((c & ACTIVE) != 0) { // ensure keep-alive
                     if ((c & CONSUME) != 0 ||
-                        U.compareAndSwapInt(this, CTL, c,
-                                            c | CONSUME))
+                        CTL.compareAndSet(this, c, c | CONSUME))
                         break;
                 }
                 else if (demand == 0L || tail == head)
                     break;
-                else if (U.compareAndSwapInt(this, CTL, c,
-                                             c | (ACTIVE | CONSUME))) {
+                else if (CTL.compareAndSet(this, c, c | (ACTIVE | CONSUME))) {
                     try {
                         e.execute(new ConsumerTask<T>(this));
                         break;
                     } catch (RuntimeException | Error ex) { // back out
                         do {} while (((c = ctl) & DISABLED) == 0 &&
                                      (c & ACTIVE) != 0 &&
-                                     !U.compareAndSwapInt(this, CTL, c,
-                                                          c & ~ACTIVE));
+                                     !CTL.weakCompareAndSetVolatile
+                                     (this, c, c & ~ACTIVE));
                         throw ex;
                     }
                 }
@@ -1300,10 +1240,10 @@ public class SubmissionPublisher<T> implements Flow.Publisher<T>,
                     break;
                 else if ((c & ACTIVE) != 0) {
                     pendingError = ex;
-                    if (U.compareAndSwapInt(this, CTL, c, c | ERROR))
+                    if (CTL.compareAndSet(this, c, c | ERROR))
                         break; // cause consumer task to exit
                 }
-                else if (U.compareAndSwapInt(this, CTL, c, DISABLED)) {
+                else if (CTL.compareAndSet(this, c, DISABLED)) {
                     Flow.Subscriber<? super T> s = subscriber;
                     if (s != null && ex != null) {
                         try {
@@ -1330,7 +1270,7 @@ public class SubmissionPublisher<T> implements Flow.Publisher<T>,
                     for (int c;;) {
                         if ((c = ctl) == DISABLED || (c & ACTIVE) == 0)
                             break;
-                        if (U.compareAndSwapInt(this, CTL, c, c & ~ACTIVE)) {
+                        if (CTL.compareAndSet(this, c, c & ~ACTIVE)) {
                             onError(ex);
                             break;
                         }
@@ -1343,8 +1283,8 @@ public class SubmissionPublisher<T> implements Flow.Publisher<T>,
             for (int c;;) {
                 if ((c = ctl) == DISABLED)
                     break;
-                if (U.compareAndSwapInt(this, CTL, c,
-                                        c | (ACTIVE | CONSUME | COMPLETE))) {
+                if (CTL.compareAndSet(this, c,
+                                      c | (ACTIVE | CONSUME | COMPLETE))) {
                     if ((c & ACTIVE) == 0)
                         startOrDisable();
                     break;
@@ -1356,8 +1296,8 @@ public class SubmissionPublisher<T> implements Flow.Publisher<T>,
             for (int c;;) {
                 if ((c = ctl) == DISABLED)
                     break;
-                if (U.compareAndSwapInt(this, CTL, c,
-                                        c | (ACTIVE | CONSUME | SUBSCRIBE))) {
+                if (CTL.compareAndSet(this, c,
+                                      c | (ACTIVE | CONSUME | SUBSCRIBE))) {
                     if ((c & ACTIVE) == 0)
                         startOrDisable();
                     break;
@@ -1375,11 +1315,11 @@ public class SubmissionPublisher<T> implements Flow.Publisher<T>,
                 if ((c = ctl) == DISABLED)
                     break;
                 else if ((c & ACTIVE) != 0) {
-                    if (U.compareAndSwapInt(this, CTL, c,
-                                            c | (CONSUME | ERROR)))
+                    if (CTL.compareAndSet(this, c,
+                                          c | (CONSUME | ERROR)))
                         break;
                 }
-                else if (U.compareAndSwapInt(this, CTL, c, DISABLED)) {
+                else if (CTL.compareAndSet(this, c, DISABLED)) {
                     detach();
                     break;
                 }
@@ -1395,19 +1335,18 @@ public class SubmissionPublisher<T> implements Flow.Publisher<T>,
                     long prev = demand, d;
                     if ((d = prev + n) < prev) // saturate
                         d = Long.MAX_VALUE;
-                    if (U.compareAndSwapLong(this, DEMAND, prev, d)) {
+                    if (DEMAND.compareAndSet(this, prev, d)) {
                         for (int c, h;;) {
                             if ((c = ctl) == DISABLED)
                                 break;
                             else if ((c & ACTIVE) != 0) {
                                 if ((c & CONSUME) != 0 ||
-                                    U.compareAndSwapInt(this, CTL, c,
-                                                        c | CONSUME))
+                                    CTL.compareAndSet(this, c, c | CONSUME))
                                     break;
                             }
                             else if ((h = head) != tail) {
-                                if (U.compareAndSwapInt(this, CTL, c,
-                                                        c | (ACTIVE|CONSUME))) {
+                                if (CTL.compareAndSet(this, c,
+                                                      c | (ACTIVE|CONSUME))) {
                                     startOrDisable();
                                     break;
                                 }
@@ -1476,16 +1415,14 @@ public class SubmissionPublisher<T> implements Flow.Publisher<T>,
             if ((s = subscriber) != null) {           // else disabled
                 for (;;) {
                     long d = demand;
-                    int c; Object[] a; int n; long i; Object x; Thread w;
+                    int c; Object[] a; int n, i; Object x; Thread w;
                     if (((c = ctl) & (ERROR | SUBSCRIBE | DISABLED)) != 0) {
                         if (!checkControl(s, c))
                             break;
                     }
                     else if ((a = array) == null || h == tail ||
                              (n = a.length) == 0 ||
-                             (x = U.getObjectVolatile
-                              (a, (i = ((long)((n - 1) & h) << ASHIFT) + ABASE)))
-                             == null) {
+                             (x = QA.getAcquire(a, i = (n - 1) & h)) == null) {
                         if (!checkEmpty(s, c))
                             break;
                     }
@@ -1494,10 +1431,10 @@ public class SubmissionPublisher<T> implements Flow.Publisher<T>,
                             break;
                     }
                     else if (((c & CONSUME) != 0 ||
-                              U.compareAndSwapInt(this, CTL, c, c | CONSUME)) &&
-                             U.compareAndSwapObject(a, i, x, null)) {
-                        U.putIntRelease(this, HEAD, ++h);
-                        U.getAndAddLong(this, DEMAND, -1L);
+                              CTL.compareAndSet(this, c, c | CONSUME)) &&
+                             QA.compareAndSet(a, i, x, null)) {
+                        HEAD.setRelease(this, ++h);
+                        DEMAND.getAndAdd(this, -1L);
                         if ((w = waiter) != null)
                             signalWaiter(w);
                         try {
@@ -1528,7 +1465,7 @@ public class SubmissionPublisher<T> implements Flow.Publisher<T>,
                 }
             }
             else if ((c & SUBSCRIBE) != 0) {
-                if (U.compareAndSwapInt(this, CTL, c, c & ~SUBSCRIBE)) {
+                if (CTL.compareAndSet(this, c, c & ~SUBSCRIBE)) {
                     try {
                         if (s != null)
                             s.onSubscribe(this);
@@ -1551,9 +1488,9 @@ public class SubmissionPublisher<T> implements Flow.Publisher<T>,
             boolean stat = true;
             if (head == tail) {
                 if ((c & CONSUME) != 0)
-                    U.compareAndSwapInt(this, CTL, c, c & ~CONSUME);
+                    CTL.compareAndSet(this, c, c & ~CONSUME);
                 else if ((c & COMPLETE) != 0) {
-                    if (U.compareAndSwapInt(this, CTL, c, DISABLED)) {
+                    if (CTL.compareAndSet(this, c, DISABLED)) {
                         try {
                             if (s != null)
                                 s.onComplete();
@@ -1561,7 +1498,7 @@ public class SubmissionPublisher<T> implements Flow.Publisher<T>,
                         }
                     }
                 }
-                else if (U.compareAndSwapInt(this, CTL, c, c & ~ACTIVE))
+                else if (CTL.compareAndSet(this, c, c & ~ACTIVE))
                     stat = false;
             }
             return stat;
@@ -1574,8 +1511,8 @@ public class SubmissionPublisher<T> implements Flow.Publisher<T>,
             boolean stat = true;
             if (demand == 0L) {
                 if ((c & CONSUME) != 0)
-                    U.compareAndSwapInt(this, CTL, c, c & ~CONSUME);
-                else if (U.compareAndSwapInt(this, CTL, c, c & ~ACTIVE))
+                    CTL.compareAndSet(this, c, c & ~CONSUME);
+                else if (CTL.compareAndSet(this, c, c & ~ACTIVE))
                     stat = false;
             }
             return stat;
@@ -1595,31 +1532,25 @@ public class SubmissionPublisher<T> implements Flow.Publisher<T>,
             onError(ex);
         }
 
-        // Unsafe mechanics
-        private static final jdk.internal.misc.Unsafe U = jdk.internal.misc.Unsafe.getUnsafe();
-        private static final long CTL;
-        private static final long TAIL;
-        private static final long HEAD;
-        private static final long DEMAND;
-        private static final int ABASE;
-        private static final int ASHIFT;
+        // VarHandle mechanics
+        private static final VarHandle CTL;
+        private static final VarHandle TAIL;
+        private static final VarHandle HEAD;
+        private static final VarHandle DEMAND;
+        private static final VarHandle QA;
 
         static {
             try {
-                CTL = U.objectFieldOffset
-                    (BufferedSubscription.class.getDeclaredField("ctl"));
-                TAIL = U.objectFieldOffset
-                    (BufferedSubscription.class.getDeclaredField("tail"));
-                HEAD = U.objectFieldOffset
-                    (BufferedSubscription.class.getDeclaredField("head"));
-                DEMAND = U.objectFieldOffset
-                    (BufferedSubscription.class.getDeclaredField("demand"));
-
-                ABASE = U.arrayBaseOffset(Object[].class);
-                int scale = U.arrayIndexScale(Object[].class);
-                if ((scale & (scale - 1)) != 0)
-                    throw new Error("data type scale not a power of two");
-                ASHIFT = 31 - Integer.numberOfLeadingZeros(scale);
+                MethodHandles.Lookup l = MethodHandles.lookup();
+                CTL = l.findVarHandle(BufferedSubscription.class, "ctl",
+                                      int.class);
+                TAIL = l.findVarHandle(BufferedSubscription.class, "tail",
+                                       int.class);
+                HEAD = l.findVarHandle(BufferedSubscription.class, "head",
+                                       int.class);
+                DEMAND = l.findVarHandle(BufferedSubscription.class, "demand",
+                                         long.class);
+                QA = MethodHandles.arrayElementVarHandle(Object[].class);
             } catch (ReflectiveOperationException e) {
                 throw new Error(e);
             }

jdk/src/java.base/share/classes/java/util/concurrent/SynchronousQueue.java

@@ -36,6 +36,8 @@
 
 package java.util.concurrent;
 
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.VarHandle;
 import java.util.AbstractQueue;
 import java.util.Collection;
 import java.util.Collections;
@@ -247,7 +249,7 @@ public class SynchronousQueue<E> extends AbstractQueue<E>
 
             boolean casNext(SNode cmp, SNode val) {
                 return cmp == next &&
-                    U.compareAndSwapObject(this, NEXT, cmp, val);
+                    SNEXT.compareAndSet(this, cmp, val);
             }
 
             /**
@@ -260,7 +262,7 @@ public class SynchronousQueue<E> extends AbstractQueue<E>
              */
             boolean tryMatch(SNode s) {
                 if (match == null &&
-                    U.compareAndSwapObject(this, MATCH, null, s)) {
+                    SMATCH.compareAndSet(this, null, s)) {
                     Thread w = waiter;
                     if (w != null) {    // waiters need at most one unpark
                         waiter = null;
@@ -275,24 +277,21 @@ public class SynchronousQueue<E> extends AbstractQueue<E>
              * Tries to cancel a wait by matching node to itself.
              */
             void tryCancel() {
-                U.compareAndSwapObject(this, MATCH, null, this);
+                SMATCH.compareAndSet(this, null, this);
             }
 
             boolean isCancelled() {
                 return match == this;
             }
 
-            // Unsafe mechanics
-            private static final jdk.internal.misc.Unsafe U = jdk.internal.misc.Unsafe.getUnsafe();
-            private static final long MATCH;
-            private static final long NEXT;
-
+            // VarHandle mechanics
+            private static final VarHandle SMATCH;
+            private static final VarHandle SNEXT;
             static {
                 try {
-                    MATCH = U.objectFieldOffset
-                        (SNode.class.getDeclaredField("match"));
-                    NEXT = U.objectFieldOffset
-                        (SNode.class.getDeclaredField("next"));
+                    MethodHandles.Lookup l = MethodHandles.lookup();
+                    SMATCH = l.findVarHandle(SNode.class, "match", SNode.class);
+                    SNEXT = l.findVarHandle(SNode.class, "next", SNode.class);
                 } catch (ReflectiveOperationException e) {
                     throw new Error(e);
                 }
@@ -304,7 +303,7 @@ public class SynchronousQueue<E> extends AbstractQueue<E>
 
         boolean casHead(SNode h, SNode nh) {
             return h == head &&
-                U.compareAndSwapObject(this, HEAD, h, nh);
+                SHEAD.compareAndSet(this, h, nh);
         }
 
         /**
@@ -451,8 +450,10 @@ public class SynchronousQueue<E> extends AbstractQueue<E>
                         continue;
                     }
                 }
-                if (spins > 0)
+                if (spins > 0) {
+                    Thread.onSpinWait();
                     spins = shouldSpin(s) ? (spins - 1) : 0;
+                }
                 else if (s.waiter == null)
                     s.waiter = w; // establish waiter so can park next iter
                 else if (!timed)
@@ -508,13 +509,12 @@ public class SynchronousQueue<E> extends AbstractQueue<E>
             }
         }
 
-        // Unsafe mechanics
-        private static final jdk.internal.misc.Unsafe U = jdk.internal.misc.Unsafe.getUnsafe();
-        private static final long HEAD;
+        // VarHandle mechanics
+        private static final VarHandle SHEAD;
         static {
             try {
-                HEAD = U.objectFieldOffset
-                    (TransferStack.class.getDeclaredField("head"));
+                MethodHandles.Lookup l = MethodHandles.lookup();
+                SHEAD = l.findVarHandle(TransferStack.class, "head", SNode.class);
             } catch (ReflectiveOperationException e) {
                 throw new Error(e);
             }
@@ -546,19 +546,19 @@ public class SynchronousQueue<E> extends AbstractQueue<E>
 
             boolean casNext(QNode cmp, QNode val) {
                 return next == cmp &&
-                    U.compareAndSwapObject(this, NEXT, cmp, val);
+                    QNEXT.compareAndSet(this, cmp, val);
             }
 
             boolean casItem(Object cmp, Object val) {
                 return item == cmp &&
-                    U.compareAndSwapObject(this, ITEM, cmp, val);
+                    QITEM.compareAndSet(this, cmp, val);
             }
 
             /**
              * Tries to cancel by CAS'ing ref to this as item.
              */
             void tryCancel(Object cmp) {
-                U.compareAndSwapObject(this, ITEM, cmp, this);
+                QITEM.compareAndSet(this, cmp, this);
             }
 
             boolean isCancelled() {
@@ -574,17 +574,14 @@ public class SynchronousQueue<E> extends AbstractQueue<E>
                 return next == this;
             }
 
-            // Unsafe mechanics
-            private static final jdk.internal.misc.Unsafe U = jdk.internal.misc.Unsafe.getUnsafe();
-            private static final long ITEM;
-            private static final long NEXT;
-
+            // VarHandle mechanics
+            private static final VarHandle QITEM;
+            private static final VarHandle QNEXT;
             static {
                 try {
-                    ITEM = U.objectFieldOffset
-                        (QNode.class.getDeclaredField("item"));
-                    NEXT = U.objectFieldOffset
-                        (QNode.class.getDeclaredField("next"));
+                    MethodHandles.Lookup l = MethodHandles.lookup();
+                    QITEM = l.findVarHandle(QNode.class, "item", Object.class);
+                    QNEXT = l.findVarHandle(QNode.class, "next", QNode.class);
                 } catch (ReflectiveOperationException e) {
                     throw new Error(e);
                 }
@@ -614,7 +611,7 @@ public class SynchronousQueue<E> extends AbstractQueue<E>
          */
         void advanceHead(QNode h, QNode nh) {
             if (h == head &&
-                U.compareAndSwapObject(this, HEAD, h, nh))
+                QHEAD.compareAndSet(this, h, nh))
                 h.next = h; // forget old next
         }
 
@@ -623,7 +620,7 @@ public class SynchronousQueue<E> extends AbstractQueue<E>
          */
         void advanceTail(QNode t, QNode nt) {
             if (tail == t)
-                U.compareAndSwapObject(this, TAIL, t, nt);
+                QTAIL.compareAndSet(this, t, nt);
         }
 
         /**
@@ -631,7 +628,7 @@ public class SynchronousQueue<E> extends AbstractQueue<E>
          */
         boolean casCleanMe(QNode cmp, QNode val) {
             return cleanMe == cmp &&
-                U.compareAndSwapObject(this, CLEANME, cmp, val);
+                QCLEANME.compareAndSet(this, cmp, val);
         }
 
         /**
@@ -752,8 +749,10 @@ public class SynchronousQueue<E> extends AbstractQueue<E>
                         continue;
                     }
                 }
-                if (spins > 0)
+                if (spins > 0) {
                     --spins;
+                    Thread.onSpinWait();
+                }
                 else if (s.waiter == null)
                     s.waiter = w;
                 else if (!timed)
@@ -817,18 +816,19 @@ public class SynchronousQueue<E> extends AbstractQueue<E>
             }
         }
 
-        private static final jdk.internal.misc.Unsafe U = jdk.internal.misc.Unsafe.getUnsafe();
-        private static final long HEAD;
-        private static final long TAIL;
-        private static final long CLEANME;
+        // VarHandle mechanics
+        private static final VarHandle QHEAD;
+        private static final VarHandle QTAIL;
+        private static final VarHandle QCLEANME;
         static {
             try {
-                HEAD = U.objectFieldOffset
-                    (TransferQueue.class.getDeclaredField("head"));
-                TAIL = U.objectFieldOffset
-                    (TransferQueue.class.getDeclaredField("tail"));
-                CLEANME = U.objectFieldOffset
-                    (TransferQueue.class.getDeclaredField("cleanMe"));
+                MethodHandles.Lookup l = MethodHandles.lookup();
+                QHEAD = l.findVarHandle(TransferQueue.class, "head",
+                                        QNode.class);
+                QTAIL = l.findVarHandle(TransferQueue.class, "tail",
+                                        QNode.class);
+                QCLEANME = l.findVarHandle(TransferQueue.class, "cleanMe",
+                                           QNode.class);
             } catch (ReflectiveOperationException e) {
                 throw new Error(e);
             }

jdk/src/java.base/share/classes/java/util/concurrent/ThreadLocalRandom.java

@@ -36,6 +36,7 @@
 package java.util.concurrent;
 
 import java.io.ObjectStreamField;
+import java.security.AccessControlContext;
 import java.util.Random;
 import java.util.Spliterator;
 import java.util.concurrent.atomic.AtomicInteger;
@@ -47,6 +48,7 @@ import java.util.stream.DoubleStream;
 import java.util.stream.IntStream;
 import java.util.stream.LongStream;
 import java.util.stream.StreamSupport;
+import jdk.internal.misc.Unsafe;
 
 /**
  * A random number generator isolated to the current thread.  Like the
@@ -95,7 +97,9 @@ public class ThreadLocalRandom extends Random {
      * ThreadLocalRandom sequence.  The dual use is a marriage of
      * convenience, but is a simple and efficient way of reducing
      * application-level overhead and footprint of most concurrent
-     * programs.
+     * programs. Even more opportunistically, we also define here
+     * other package-private utilities that access Thread class
+     * fields.
      *
      * Even though this class subclasses java.util.Random, it uses the
      * same basic algorithm as java.util.SplittableRandom.  (See its
@@ -958,6 +962,49 @@ public class ThreadLocalRandom extends Random {
         return r;
     }
 
+    // Support for other package-private ThreadLocal access
+
+    /**
+     * Erases ThreadLocals by nulling out Thread maps.
+     */
+    static final void eraseThreadLocals(Thread thread) {
+        U.putObject(thread, THREADLOCALS, null);
+        U.putObject(thread, INHERITABLETHREADLOCALS, null);
+    }
+
+    static final void setInheritedAccessControlContext(Thread thread,
+                                                       AccessControlContext acc) {
+        U.putObjectRelease(thread, INHERITEDACCESSCONTROLCONTEXT, acc);
+    }
+
+    /**
+     * Returns a new group with the system ThreadGroup (the
+     * topmost, parent-less group) as parent.  Uses Unsafe to
+     * traverse Thread.group and ThreadGroup.parent fields.
+     */
+    static final ThreadGroup createThreadGroup(String name) {
+        if (name == null)
+            throw new NullPointerException();
+        try {
+            long tg = U.objectFieldOffset
+                (Thread.class.getDeclaredField("group"));
+            long gp = U.objectFieldOffset
+                (ThreadGroup.class.getDeclaredField("parent"));
+            ThreadGroup group = (ThreadGroup)
+                U.getObject(Thread.currentThread(), tg);
+            while (group != null) {
+                ThreadGroup parent = (ThreadGroup)U.getObject(group, gp);
+                if (parent == null)
+                    return new ThreadGroup(group, name);
+                group = parent;
+            }
+        } catch (ReflectiveOperationException e) {
+            throw new Error(e);
+        }
+        // fall through if null as cannot-happen safeguard
+        throw new Error("Cannot create ThreadGroup");
+    }
+
     // Serialization support
 
     private static final long serialVersionUID = -5851777807851030925L;
@@ -1022,10 +1069,13 @@ public class ThreadLocalRandom extends Random {
     static final String BAD_SIZE  = "size must be non-negative";
 
     // Unsafe mechanics
-    private static final jdk.internal.misc.Unsafe U = jdk.internal.misc.Unsafe.getUnsafe();
+    private static final Unsafe U = Unsafe.getUnsafe();
     private static final long SEED;
     private static final long PROBE;
     private static final long SECONDARY;
+    private static final long THREADLOCALS;
+    private static final long INHERITABLETHREADLOCALS;
+    private static final long INHERITEDACCESSCONTROLCONTEXT;
     static {
         try {
             SEED = U.objectFieldOffset
@@ -1034,6 +1084,12 @@ public class ThreadLocalRandom extends Random {
                 (Thread.class.getDeclaredField("threadLocalRandomProbe"));
             SECONDARY = U.objectFieldOffset
                 (Thread.class.getDeclaredField("threadLocalRandomSecondarySeed"));
+            THREADLOCALS = U.objectFieldOffset
+                (Thread.class.getDeclaredField("threadLocals"));
+            INHERITABLETHREADLOCALS = U.objectFieldOffset
+                (Thread.class.getDeclaredField("inheritableThreadLocals"));
+            INHERITEDACCESSCONTROLCONTEXT = U.objectFieldOffset
+                (Thread.class.getDeclaredField("inheritedAccessControlContext"));
         } catch (ReflectiveOperationException e) {
             throw new Error(e);
         }

jdk/src/java.base/share/classes/java/util/concurrent/atomic/AtomicBoolean.java

@@ -35,27 +35,26 @@
 
 package java.util.concurrent.atomic;
 
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.VarHandle;
+
 /**
  * A {@code boolean} value that may be updated atomically. See the
- * {@link java.util.concurrent.atomic} package specification for
- * description of the properties of atomic variables. An
- * {@code AtomicBoolean} is used in applications such as atomically
- * updated flags, and cannot be used as a replacement for a
- * {@link java.lang.Boolean}.
+ * {@link VarHandle} specification for descriptions of the properties
+ * of atomic accesses. An {@code AtomicBoolean} is used in
+ * applications such as atomically updated flags, and cannot be used
+ * as a replacement for a {@link java.lang.Boolean}.
  *
  * @since 1.5
  * @author Doug Lea
  */
 public class AtomicBoolean implements java.io.Serializable {
     private static final long serialVersionUID = 4654671469794556979L;
-
-    private static final jdk.internal.misc.Unsafe U = jdk.internal.misc.Unsafe.getUnsafe();
-    private static final long VALUE;
-
+    private static final VarHandle VALUE;
     static {
         try {
-            VALUE = U.objectFieldOffset
-                (AtomicBoolean.class.getDeclaredField("value"));
+            MethodHandles.Lookup l = MethodHandles.lookup();
+            VALUE = l.findVarHandle(AtomicBoolean.class, "value", int.class);
         } catch (ReflectiveOperationException e) {
             throw new Error(e);
         }
@@ -79,7 +78,8 @@ public class AtomicBoolean implements java.io.Serializable {
     }
 
     /**
-     * Returns the current value.
+     * Returns the current value,
+     * with memory effects as specified by {@link VarHandle#getVolatile}.
      *
      * @return the current value
      */
@@ -88,40 +88,39 @@ public class AtomicBoolean implements java.io.Serializable {
     }
 
     /**
-     * Atomically sets the value to the given updated value
-     * if the current value {@code ==} the expected value.
+     * Atomically sets the value to {@code newValue}
+     * if the current value {@code == expectedValue},
+     * with memory effects as specified by {@link VarHandle#compareAndSet}.
      *
-     * @param expect the expected value
-     * @param update the new value
+     * @param expectedValue the expected value
+     * @param newValue the new value
      * @return {@code true} if successful. False return indicates that
      * the actual value was not equal to the expected value.
      */
-    public final boolean compareAndSet(boolean expect, boolean update) {
-        return U.compareAndSwapInt(this, VALUE,
-                                   (expect ? 1 : 0),
-                                   (update ? 1 : 0));
+    public final boolean compareAndSet(boolean expectedValue, boolean newValue) {
+        return VALUE.compareAndSet(this,
+                                   (expectedValue ? 1 : 0),
+                                   (newValue ? 1 : 0));
     }
 
     /**
-     * Atomically sets the value to the given updated value
-     * if the current value {@code ==} the expected value.
+     * Possibly atomically sets the value to {@code newValue}
+     * if the current value {@code == expectedValue},
+     * with memory effects as specified by {@link VarHandle#weakCompareAndSet}.
      *
-     * <p><a href="package-summary.html#weakCompareAndSet">May fail
-     * spuriously and does not provide ordering guarantees</a>, so is
-     * only rarely an appropriate alternative to {@code compareAndSet}.
-     *
-     * @param expect the expected value
-     * @param update the new value
+     * @param expectedValue the expected value
+     * @param newValue the new value
      * @return {@code true} if successful
      */
-    public boolean weakCompareAndSet(boolean expect, boolean update) {
-        return U.compareAndSwapInt(this, VALUE,
-                                   (expect ? 1 : 0),
-                                   (update ? 1 : 0));
+    public boolean weakCompareAndSet(boolean expectedValue, boolean newValue) {
+        return VALUE.weakCompareAndSet(this,
+                                       (expectedValue ? 1 : 0),
+                                       (newValue ? 1 : 0));
     }
 
     /**
-     * Unconditionally sets to the given value.
+     * Sets the value to {@code newValue},
+     * with memory effects as specified by {@link VarHandle#setVolatile}.
      *
      * @param newValue the new value
      */
@@ -130,17 +129,19 @@ public class AtomicBoolean implements java.io.Serializable {
     }
 
     /**
-     * Eventually sets to the given value.
+     * Sets the value to {@code newValue},
+     * with memory effects as specified by {@link VarHandle#setRelease}.
      *
      * @param newValue the new value
      * @since 1.6
      */
     public final void lazySet(boolean newValue) {
-        U.putIntRelease(this, VALUE, (newValue ? 1 : 0));
+        VALUE.setRelease(this, (newValue ? 1 : 0));
     }
 
     /**
-     * Atomically sets to the given value and returns the previous value.
+     * Atomically sets the value to {@code newValue} and returns the old value,
+     * with memory effects as specified by {@link VarHandle#getAndSet}.
      *
      * @param newValue the new value
      * @return the previous value
@@ -161,4 +162,178 @@ public class AtomicBoolean implements java.io.Serializable {
         return Boolean.toString(get());
     }
 
+    // jdk9
+
+    /**
+     * Returns the current value, with memory semantics of reading as
+     * if the variable was declared non-{@code volatile}.
+     *
+     * @return the value
+     * @since 9
+     */
+    public final boolean getPlain() {
+        return (int)VALUE.get(this) != 0;
+    }
+
+    /**
+     * Sets the value to {@code newValue}, with memory semantics
+     * of setting as if the variable was declared non-{@code volatile}
+     * and non-{@code final}.
+     *
+     * @param newValue the new value
+     * @since 9
+     */
+    public final void setPlain(boolean newValue) {
+        VALUE.set(this, newValue ? 1 : 0);
+    }
+
+    /**
+     * Returns the current value,
+     * with memory effects as specified by {@link VarHandle#getOpaque}.
+     *
+     * @return the value
+     * @since 9
+     */
+    public final boolean getOpaque() {
+        return (int)VALUE.getOpaque(this) != 0;
+    }
+
+    /**
+     * Sets the value to {@code newValue},
+     * with memory effects as specified by {@link VarHandle#setOpaque}.
+     *
+     * @param newValue the new value
+     * @since 9
+     */
+    public final void setOpaque(boolean newValue) {
+        VALUE.setOpaque(this, newValue ? 1 : 0);
+    }
+
+    /**
+     * Returns the current value,
+     * with memory effects as specified by {@link VarHandle#getAcquire}.
+     *
+     * @return the value
+     * @since 9
+     */
+    public final boolean getAcquire() {
+        return (int)VALUE.getAcquire(this) != 0;
+    }
+
+    /**
+     * Sets the value to {@code newValue},
+     * with memory effects as specified by {@link VarHandle#setRelease}.
+     *
+     * @param newValue the new value
+     * @since 9
+     */
+    public final void setRelease(boolean newValue) {
+        VALUE.setRelease(this, newValue ? 1 : 0);
+    }
+
+    /**
+     * Atomically sets the value to {@code newValue} if the current value,
+     * referred to as the <em>witness value</em>, {@code == expectedValue},
+     * with memory effects as specified by
+     * {@link VarHandle#compareAndExchange}.
+     *
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return the witness value, which will be the same as the
+     * expected value if successful
+     * @since 9
+     */
+    public final boolean compareAndExchange(boolean expectedValue, boolean newValue) {
+        return (int)VALUE.compareAndExchange(this,
+                                             (expectedValue ? 1 : 0),
+                                             (newValue ? 1 : 0)) != 0;
+    }
+
+    /**
+     * Atomically sets the value to {@code newValue} if the current value,
+     * referred to as the <em>witness value</em>, {@code == expectedValue},
+     * with memory effects as specified by
+     * {@link VarHandle#compareAndExchangeAcquire}.
+     *
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return the witness value, which will be the same as the
+     * expected value if successful
+     * @since 9
+     */
+    public final boolean compareAndExchangeAcquire(boolean expectedValue, boolean newValue) {
+        return (int)VALUE.compareAndExchangeAcquire(this,
+                                                    (expectedValue ? 1 : 0),
+                                                    (newValue ? 1 : 0)) != 0;
+    }
+
+    /**
+     * Atomically sets the value to {@code newValue} if the current value,
+     * referred to as the <em>witness value</em>, {@code == expectedValue},
+     * with memory effects as specified by
+     * {@link VarHandle#compareAndExchangeRelease}.
+     *
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return the witness value, which will be the same as the
+     * expected value if successful
+     * @since 9
+     */
+    public final boolean compareAndExchangeRelease(boolean expectedValue, boolean newValue) {
+        return (int)VALUE.compareAndExchangeRelease(this,
+                                                    (expectedValue ? 1 : 0),
+                                                    (newValue ? 1 : 0)) != 0;
+    }
+
+    /**
+     * Possibly atomically sets the value to {@code newValue} if the current
+     * value {@code == expectedValue},
+     * with memory effects as specified by
+     * {@link VarHandle#weakCompareAndSetVolatile}.
+     *
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return {@code true} if successful
+     * @since 9
+     */
+    public final boolean weakCompareAndSetVolatile(boolean expectedValue, boolean newValue) {
+        return VALUE.weakCompareAndSetVolatile(this,
+                                               (expectedValue ? 1 : 0),
+                                               (newValue ? 1 : 0));
+    }
+
+    /**
+     * Possibly atomically sets the value to {@code newValue} if the current
+     * value {@code == expectedValue},
+     * with memory effects as specified by
+     * {@link VarHandle#weakCompareAndSetAcquire}.
+     *
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return {@code true} if successful
+     * @since 9
+     */
+    public final boolean weakCompareAndSetAcquire(boolean expectedValue, boolean newValue) {
+        return VALUE.weakCompareAndSetAcquire(this,
+                                              (expectedValue ? 1 : 0),
+                                              (newValue ? 1 : 0));
+    }
+
+    /**
+     * Possibly atomically sets the value to {@code newValue} if the current
+     * value {@code == expectedValue},
+     * with memory effects as specified by
+     * {@link VarHandle#weakCompareAndSetRelease}.
+     *
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return {@code true} if successful
+     * @since 9
+     */
+    public final boolean weakCompareAndSetRelease(boolean expectedValue, boolean newValue) {
+        return VALUE.weakCompareAndSetRelease(this,
+                                              (expectedValue ? 1 : 0),
+                                              (newValue ? 1 : 0));
+    }
+
 }

jdk/src/java.base/share/classes/java/util/concurrent/atomic/AtomicInteger.java

@@ -35,32 +35,30 @@
 
 package java.util.concurrent.atomic;
 
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.VarHandle;
 import java.util.function.IntBinaryOperator;
 import java.util.function.IntUnaryOperator;
 
 /**
  * An {@code int} value that may be updated atomically.  See the
- * {@link java.util.concurrent.atomic} package specification for
- * description of the properties of atomic variables. An
- * {@code AtomicInteger} is used in applications such as atomically
- * incremented counters, and cannot be used as a replacement for an
- * {@link java.lang.Integer}. However, this class does extend
- * {@code Number} to allow uniform access by tools and utilities that
- * deal with numerically-based classes.
+ * {@link VarHandle} specification for descriptions of the properties
+ * of atomic accesses. An {@code AtomicInteger} is used in
+ * applications such as atomically incremented counters, and cannot be
+ * used as a replacement for an {@link java.lang.Integer}. However,
+ * this class does extend {@code Number} to allow uniform access by
+ * tools and utilities that deal with numerically-based classes.
  *
  * @since 1.5
  * @author Doug Lea
  */
 public class AtomicInteger extends Number implements java.io.Serializable {
     private static final long serialVersionUID = 6214790243416807050L;
-
-    private static final jdk.internal.misc.Unsafe U = jdk.internal.misc.Unsafe.getUnsafe();
-    private static final long VALUE;
-
+    private static final VarHandle VALUE;
     static {
         try {
-            VALUE = U.objectFieldOffset
-                (AtomicInteger.class.getDeclaredField("value"));
+            MethodHandles.Lookup l = MethodHandles.lookup();
+            VALUE = l.findVarHandle(AtomicInteger.class, "value", int.class);
         } catch (ReflectiveOperationException e) {
             throw new Error(e);
         }
@@ -84,7 +82,8 @@ public class AtomicInteger extends Number implements java.io.Serializable {
     }
 
     /**
-     * Gets the current value.
+     * Returns the current value,
+     * with memory effects as specified by {@link VarHandle#getVolatile}.
      *
      * @return the current value
      */
@@ -93,7 +92,8 @@ public class AtomicInteger extends Number implements java.io.Serializable {
     }
 
     /**
-     * Sets to the given value.
+     * Sets the value to {@code newValue},
+     * with memory effects as specified by {@link VarHandle#setVolatile}.
      *
      * @param newValue the new value
      */
@@ -102,108 +102,122 @@ public class AtomicInteger extends Number implements java.io.Serializable {
     }
 
     /**
-     * Eventually sets to the given value.
+     * Sets the value to {@code newValue},
+     * with memory effects as specified by {@link VarHandle#setRelease}.
      *
      * @param newValue the new value
      * @since 1.6
      */
     public final void lazySet(int newValue) {
-        U.putIntRelease(this, VALUE, newValue);
+        VALUE.setRelease(this, newValue);
     }
 
     /**
-     * Atomically sets to the given value and returns the old value.
+     * Atomically sets the value to {@code newValue} and returns the old value,
+     * with memory effects as specified by {@link VarHandle#getAndSet}.
      *
      * @param newValue the new value
      * @return the previous value
      */
     public final int getAndSet(int newValue) {
-        return U.getAndSetInt(this, VALUE, newValue);
+        return (int)VALUE.getAndSet(this, newValue);
     }
 
     /**
-     * Atomically sets the value to the given updated value
-     * if the current value {@code ==} the expected value.
+     * Atomically sets the value to {@code newValue}
+     * if the current value {@code == expectedValue},
+     * with memory effects as specified by {@link VarHandle#compareAndSet}.
      *
-     * @param expect the expected value
-     * @param update the new value
+     * @param expectedValue the expected value
+     * @param newValue the new value
      * @return {@code true} if successful. False return indicates that
      * the actual value was not equal to the expected value.
      */
-    public final boolean compareAndSet(int expect, int update) {
-        return U.compareAndSwapInt(this, VALUE, expect, update);
+    public final boolean compareAndSet(int expectedValue, int newValue) {
+        return VALUE.compareAndSet(this, expectedValue, newValue);
     }
 
     /**
-     * Atomically sets the value to the given updated value
-     * if the current value {@code ==} the expected value.
+     * Possibly atomically sets the value to {@code newValue}
+     * if the current value {@code == expectedValue},
+     * with memory effects as specified by {@link VarHandle#weakCompareAndSet}.
      *
-     * <p><a href="package-summary.html#weakCompareAndSet">May fail
-     * spuriously and does not provide ordering guarantees</a>, so is
-     * only rarely an appropriate alternative to {@code compareAndSet}.
-     *
-     * @param expect the expected value
-     * @param update the new value
+     * @param expectedValue the expected value
+     * @param newValue the new value
      * @return {@code true} if successful
      */
-    public final boolean weakCompareAndSet(int expect, int update) {
-        return U.compareAndSwapInt(this, VALUE, expect, update);
+    public final boolean weakCompareAndSet(int expectedValue, int newValue) {
+        return VALUE.weakCompareAndSet(this, expectedValue, newValue);
     }
 
     /**
-     * Atomically increments by one the current value.
+     * Atomically increments the current value,
+     * with memory effects as specified by {@link VarHandle#getAndAdd}.
+     *
+     * <p>Equivalent to {@code getAndAdd(1)}.
      *
      * @return the previous value
      */
     public final int getAndIncrement() {
-        return U.getAndAddInt(this, VALUE, 1);
+        return (int)VALUE.getAndAdd(this, 1);
     }
 
     /**
-     * Atomically decrements by one the current value.
+     * Atomically decrements the current value,
+     * with memory effects as specified by {@link VarHandle#getAndAdd}.
+     *
+     * <p>Equivalent to {@code getAndAdd(-1)}.
      *
      * @return the previous value
      */
     public final int getAndDecrement() {
-        return U.getAndAddInt(this, VALUE, -1);
+        return (int)VALUE.getAndAdd(this, -1);
     }
 
     /**
-     * Atomically adds the given value to the current value.
+     * Atomically adds the given value to the current value,
+     * with memory effects as specified by {@link VarHandle#getAndAdd}.
      *
      * @param delta the value to add
      * @return the previous value
      */
     public final int getAndAdd(int delta) {
-        return U.getAndAddInt(this, VALUE, delta);
+        return (int)VALUE.getAndAdd(this, delta);
     }
 
     /**
-     * Atomically increments by one the current value.
+     * Atomically increments the current value,
+     * with memory effects as specified by {@link VarHandle#addAndGet}.
+     *
+     * <p>Equivalent to {@code addAndGet(1)}.
      *
      * @return the updated value
      */
     public final int incrementAndGet() {
-        return U.getAndAddInt(this, VALUE, 1) + 1;
+        return (int)VALUE.addAndGet(this, 1);
     }
 
     /**
-     * Atomically decrements by one the current value.
+     * Atomically decrements the current value,
+     * with memory effects as specified by {@link VarHandle#addAndGet}.
+     *
+     * <p>Equivalent to {@code addAndGet(-1)}.
      *
      * @return the updated value
      */
     public final int decrementAndGet() {
-        return U.getAndAddInt(this, VALUE, -1) - 1;
+        return (int)VALUE.addAndGet(this, -1);
     }
 
     /**
-     * Atomically adds the given value to the current value.
+     * Atomically adds the given value to the current value,
+     * with memory effects as specified by {@link VarHandle#addAndGet}.
      *
      * @param delta the value to add
      * @return the updated value
      */
     public final int addAndGet(int delta) {
-        return U.getAndAddInt(this, VALUE, delta) + delta;
+        return (int)VALUE.addAndGet(this, delta);
     }
 
     /**
@@ -217,12 +231,14 @@ public class AtomicInteger extends Number implements java.io.Serializable {
      * @since 1.8
      */
     public final int getAndUpdate(IntUnaryOperator updateFunction) {
-        int prev, next;
-        do {
-            prev = get();
-            next = updateFunction.applyAsInt(prev);
-        } while (!compareAndSet(prev, next));
-        return prev;
+        int prev = get(), next = 0;
+        for (boolean haveNext = false;;) {
+            if (!haveNext)
+                next = updateFunction.applyAsInt(prev);
+            if (weakCompareAndSetVolatile(prev, next))
+                return prev;
+            haveNext = (prev == (prev = get()));
+        }
     }
 
     /**
@@ -236,12 +252,14 @@ public class AtomicInteger extends Number implements java.io.Serializable {
      * @since 1.8
      */
     public final int updateAndGet(IntUnaryOperator updateFunction) {
-        int prev, next;
-        do {
-            prev = get();
-            next = updateFunction.applyAsInt(prev);
-        } while (!compareAndSet(prev, next));
-        return next;
+        int prev = get(), next = 0;
+        for (boolean haveNext = false;;) {
+            if (!haveNext)
+                next = updateFunction.applyAsInt(prev);
+            if (weakCompareAndSetVolatile(prev, next))
+                return next;
+            haveNext = (prev == (prev = get()));
+        }
     }
 
     /**
@@ -260,12 +278,14 @@ public class AtomicInteger extends Number implements java.io.Serializable {
      */
     public final int getAndAccumulate(int x,
                                       IntBinaryOperator accumulatorFunction) {
-        int prev, next;
-        do {
-            prev = get();
-            next = accumulatorFunction.applyAsInt(prev, x);
-        } while (!compareAndSet(prev, next));
-        return prev;
+        int prev = get(), next = 0;
+        for (boolean haveNext = false;;) {
+            if (!haveNext)
+                next = accumulatorFunction.applyAsInt(prev, x);
+            if (weakCompareAndSetVolatile(prev, next))
+                return prev;
+            haveNext = (prev == (prev = get()));
+        }
     }
 
     /**
@@ -284,12 +304,14 @@ public class AtomicInteger extends Number implements java.io.Serializable {
      */
     public final int accumulateAndGet(int x,
                                       IntBinaryOperator accumulatorFunction) {
-        int prev, next;
-        do {
-            prev = get();
-            next = accumulatorFunction.applyAsInt(prev, x);
-        } while (!compareAndSet(prev, next));
-        return next;
+        int prev = get(), next = 0;
+        for (boolean haveNext = false;;) {
+            if (!haveNext)
+                next = accumulatorFunction.applyAsInt(prev, x);
+            if (weakCompareAndSetVolatile(prev, next))
+                return next;
+            haveNext = (prev == (prev = get()));
+        }
     }
 
     /**
@@ -301,7 +323,10 @@ public class AtomicInteger extends Number implements java.io.Serializable {
     }
 
     /**
-     * Returns the value of this {@code AtomicInteger} as an {@code int}.
+     * Returns the current value of this {@code AtomicInteger} as an
+     * {@code int},
+     * with memory effects as specified by {@link VarHandle#getVolatile}.
+     *
      * Equivalent to {@link #get()}.
      */
     public int intValue() {
@@ -309,8 +334,9 @@ public class AtomicInteger extends Number implements java.io.Serializable {
     }
 
     /**
-     * Returns the value of this {@code AtomicInteger} as a {@code long}
-     * after a widening primitive conversion.
+     * Returns the current value of this {@code AtomicInteger} as a
+     * {@code long} after a widening primitive conversion,
+     * with memory effects as specified by {@link VarHandle#getVolatile}.
      * @jls 5.1.2 Widening Primitive Conversions
      */
     public long longValue() {
@@ -318,8 +344,9 @@ public class AtomicInteger extends Number implements java.io.Serializable {
     }
 
     /**
-     * Returns the value of this {@code AtomicInteger} as a {@code float}
-     * after a widening primitive conversion.
+     * Returns the current value of this {@code AtomicInteger} as a
+     * {@code float} after a widening primitive conversion,
+     * with memory effects as specified by {@link VarHandle#getVolatile}.
      * @jls 5.1.2 Widening Primitive Conversions
      */
     public float floatValue() {
@@ -327,12 +354,175 @@ public class AtomicInteger extends Number implements java.io.Serializable {
     }
 
     /**
-     * Returns the value of this {@code AtomicInteger} as a {@code double}
-     * after a widening primitive conversion.
+     * Returns the current value of this {@code AtomicInteger} as a
+     * {@code double} after a widening primitive conversion,
+     * with memory effects as specified by {@link VarHandle#getVolatile}.
      * @jls 5.1.2 Widening Primitive Conversions
      */
     public double doubleValue() {
         return (double)get();
     }
 
+    // jdk9
+
+    /**
+     * Returns the current value, with memory semantics of reading as
+     * if the variable was declared non-{@code volatile}.
+     *
+     * @return the value
+     * @since 9
+     */
+    public final int getPlain() {
+        return (int)VALUE.get(this);
+    }
+
+    /**
+     * Sets the value to {@code newValue}, with memory semantics
+     * of setting as if the variable was declared non-{@code volatile}
+     * and non-{@code final}.
+     *
+     * @param newValue the new value
+     * @since 9
+     */
+    public final void setPlain(int newValue) {
+        VALUE.set(this, newValue);
+    }
+
+    /**
+     * Returns the current value,
+     * with memory effects as specified by {@link VarHandle#getOpaque}.
+     *
+     * @return the value
+     * @since 9
+     */
+    public final int getOpaque() {
+        return (int)VALUE.getOpaque(this);
+    }
+
+    /**
+     * Sets the value to {@code newValue},
+     * with memory effects as specified by {@link VarHandle#setOpaque}.
+     *
+     * @param newValue the new value
+     * @since 9
+     */
+    public final void setOpaque(int newValue) {
+        VALUE.setOpaque(this, newValue);
+    }
+
+    /**
+     * Returns the current value,
+     * with memory effects as specified by {@link VarHandle#getAcquire}.
+     *
+     * @return the value
+     * @since 9
+     */
+    public final int getAcquire() {
+        return (int)VALUE.getAcquire(this);
+    }
+
+    /**
+     * Sets the value to {@code newValue},
+     * with memory effects as specified by {@link VarHandle#setRelease}.
+     *
+     * @param newValue the new value
+     * @since 9
+     */
+    public final void setRelease(int newValue) {
+        VALUE.setRelease(this, newValue);
+    }
+
+    /**
+     * Atomically sets the value to {@code newValue} if the current value,
+     * referred to as the <em>witness value</em>, {@code == expectedValue},
+     * with memory effects as specified by
+     * {@link VarHandle#compareAndExchange}.
+     *
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return the witness value, which will be the same as the
+     * expected value if successful
+     * @since 9
+     */
+    public final int compareAndExchange(int expectedValue, int newValue) {
+        return (int)VALUE.compareAndExchange(this, expectedValue, newValue);
+    }
+
+    /**
+     * Atomically sets the value to {@code newValue} if the current value,
+     * referred to as the <em>witness value</em>, {@code == expectedValue},
+     * with memory effects as specified by
+     * {@link VarHandle#compareAndExchangeAcquire}.
+     *
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return the witness value, which will be the same as the
+     * expected value if successful
+     * @since 9
+     */
+    public final int compareAndExchangeAcquire(int expectedValue, int newValue) {
+        return (int)VALUE.compareAndExchangeAcquire(this, expectedValue, newValue);
+    }
+
+    /**
+     * Atomically sets the value to {@code newValue} if the current value,
+     * referred to as the <em>witness value</em>, {@code == expectedValue},
+     * with memory effects as specified by
+     * {@link VarHandle#compareAndExchangeRelease}.
+     *
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return the witness value, which will be the same as the
+     * expected value if successful
+     * @since 9
+     */
+    public final int compareAndExchangeRelease(int expectedValue, int newValue) {
+        return (int)VALUE.compareAndExchangeRelease(this, expectedValue, newValue);
+    }
+
+    /**
+     * Possibly atomically sets the value to {@code newValue} if
+     * the current value {@code == expectedValue},
+     * with memory effects as specified by
+     * {@link VarHandle#weakCompareAndSetVolatile}.
+     *
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return {@code true} if successful
+     * @since 9
+     */
+    public final boolean weakCompareAndSetVolatile(int expectedValue, int newValue) {
+        return VALUE.weakCompareAndSetVolatile(this, expectedValue, newValue);
+    }
+
+    /**
+     * Possibly atomically sets the value to {@code newValue} if
+     * the current value {@code == expectedValue},
+     * with memory effects as specified by
+     * {@link VarHandle#weakCompareAndSetAcquire}.
+     *
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return {@code true} if successful
+     * @since 9
+     */
+    public final boolean weakCompareAndSetAcquire(int expectedValue, int newValue) {
+        return VALUE.weakCompareAndSetAcquire(this, expectedValue, newValue);
+    }
+
+    /**
+     * Possibly atomically sets the value to {@code newValue} if
+     * the current value {@code == expectedValue},
+     * with memory effects as specified by
+     * {@link VarHandle#weakCompareAndSetRelease}.
+     *
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return {@code true} if successful
+     * @since 9
+     */
+    public final boolean weakCompareAndSetRelease(int expectedValue, int newValue) {
+        return VALUE.weakCompareAndSetRelease(this, expectedValue, newValue);
+    }
+
 }

jdk/src/java.base/share/classes/java/util/concurrent/atomic/AtomicIntegerArray.java

@@ -35,44 +35,24 @@
 
 package java.util.concurrent.atomic;
 
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.VarHandle;
 import java.util.function.IntBinaryOperator;
 import java.util.function.IntUnaryOperator;
 
 /**
  * An {@code int} array in which elements may be updated atomically.
- * See the {@link java.util.concurrent.atomic} package
- * specification for description of the properties of atomic
- * variables.
+ * See the {@link VarHandle} specification for descriptions of the
+ * properties of atomic accesses.
  * @since 1.5
  * @author Doug Lea
  */
 public class AtomicIntegerArray implements java.io.Serializable {
     private static final long serialVersionUID = 2862133569453604235L;
-
-    private static final jdk.internal.misc.Unsafe U = jdk.internal.misc.Unsafe.getUnsafe();
-    private static final int ABASE;
-    private static final int ASHIFT;
+    private static final VarHandle AA
+        = MethodHandles.arrayElementVarHandle(int[].class);
     private final int[] array;
 
-    static {
-        ABASE = U.arrayBaseOffset(int[].class);
-        int scale = U.arrayIndexScale(int[].class);
-        if ((scale & (scale - 1)) != 0)
-            throw new Error("array index scale not a power of two");
-        ASHIFT = 31 - Integer.numberOfLeadingZeros(scale);
-    }
-
-    private long checkedByteOffset(int i) {
-        if (i < 0 || i >= array.length)
-            throw new IndexOutOfBoundsException("index " + i);
-
-        return byteOffset(i);
-    }
-
-    private static long byteOffset(int i) {
-        return ((long) i << ASHIFT) + ABASE;
-    }
-
     /**
      * Creates a new AtomicIntegerArray of the given length, with all
      * elements initially zero.
@@ -105,147 +85,155 @@ public class AtomicIntegerArray implements java.io.Serializable {
     }
 
     /**
-     * Gets the current value at position {@code i}.
+     * Returns the current value of the element at index {@code i},
+     * with memory effects as specified by {@link VarHandle#getVolatile}.
      *
      * @param i the index
      * @return the current value
      */
     public final int get(int i) {
-        return getRaw(checkedByteOffset(i));
-    }
-
-    private int getRaw(long offset) {
-        return U.getIntVolatile(array, offset);
+        return (int)AA.getVolatile(array, i);
     }
 
     /**
-     * Sets the element at position {@code i} to the given value.
+     * Sets the element at index {@code i} to {@code newValue},
+     * with memory effects as specified by {@link VarHandle#setVolatile}.
      *
      * @param i the index
      * @param newValue the new value
      */
     public final void set(int i, int newValue) {
-        U.putIntVolatile(array, checkedByteOffset(i), newValue);
+        AA.setVolatile(array, i, newValue);
     }
 
     /**
-     * Eventually sets the element at position {@code i} to the given value.
+     * Sets the element at index {@code i} to {@code newValue},
+     * with memory effects as specified by {@link VarHandle#setRelease}.
      *
      * @param i the index
      * @param newValue the new value
      * @since 1.6
      */
     public final void lazySet(int i, int newValue) {
-        U.putIntRelease(array, checkedByteOffset(i), newValue);
+        AA.setRelease(array, i, newValue);
     }
 
     /**
-     * Atomically sets the element at position {@code i} to the given
-     * value and returns the old value.
+     * Atomically sets the element at index {@code i} to {@code
+     * newValue} and returns the old value,
+     * with memory effects as specified by {@link VarHandle#getAndSet}.
      *
      * @param i the index
      * @param newValue the new value
      * @return the previous value
      */
     public final int getAndSet(int i, int newValue) {
-        return U.getAndSetInt(array, checkedByteOffset(i), newValue);
+        return (int)AA.getAndSet(array, i, newValue);
     }
 
     /**
-     * Atomically sets the element at position {@code i} to the given
-     * updated value if the current value {@code ==} the expected value.
+     * Atomically sets the element at index {@code i} to {@code
+     * newValue} if the element's current value {@code == expectedValue},
+     * with memory effects as specified by {@link VarHandle#compareAndSet}.
      *
      * @param i the index
-     * @param expect the expected value
-     * @param update the new value
+     * @param expectedValue the expected value
+     * @param newValue the new value
      * @return {@code true} if successful. False return indicates that
      * the actual value was not equal to the expected value.
      */
-    public final boolean compareAndSet(int i, int expect, int update) {
-        return compareAndSetRaw(checkedByteOffset(i), expect, update);
-    }
-
-    private boolean compareAndSetRaw(long offset, int expect, int update) {
-        return U.compareAndSwapInt(array, offset, expect, update);
+    public final boolean compareAndSet(int i, int expectedValue, int newValue) {
+        return AA.compareAndSet(array, i, expectedValue, newValue);
     }
 
     /**
-     * Atomically sets the element at position {@code i} to the given
-     * updated value if the current value {@code ==} the expected value.
-     *
-     * <p><a href="package-summary.html#weakCompareAndSet">May fail
-     * spuriously and does not provide ordering guarantees</a>, so is
-     * only rarely an appropriate alternative to {@code compareAndSet}.
+     * Possibly atomically sets the element at index {@code i} to
+     * {@code newValue} if the element's current value {@code == expectedValue},
+     * with memory effects as specified by {@link VarHandle#weakCompareAndSet}.
      *
      * @param i the index
-     * @param expect the expected value
-     * @param update the new value
+     * @param expectedValue the expected value
+     * @param newValue the new value
      * @return {@code true} if successful
      */
-    public final boolean weakCompareAndSet(int i, int expect, int update) {
-        return compareAndSet(i, expect, update);
+    public final boolean weakCompareAndSet(int i, int expectedValue, int newValue) {
+        return AA.weakCompareAndSet(array, i, expectedValue, newValue);
     }
 
     /**
-     * Atomically increments by one the element at index {@code i}.
+     * Atomically increments the value of the element at index {@code i},
+     * with memory effects as specified by {@link VarHandle#getAndAdd}.
+     *
+     * <p>Equivalent to {@code getAndAdd(i, 1)}.
      *
      * @param i the index
      * @return the previous value
      */
     public final int getAndIncrement(int i) {
-        return getAndAdd(i, 1);
+        return (int)AA.getAndAdd(array, i, 1);
     }
 
     /**
-     * Atomically decrements by one the element at index {@code i}.
+     * Atomically decrements the value of the element at index {@code i},
+     * with memory effects as specified by {@link VarHandle#getAndAdd}.
+     *
+     * <p>Equivalent to {@code getAndAdd(i, -1)}.
      *
      * @param i the index
      * @return the previous value
      */
     public final int getAndDecrement(int i) {
-        return getAndAdd(i, -1);
+        return (int)AA.getAndAdd(array, i, -1);
     }
 
     /**
-     * Atomically adds the given value to the element at index {@code i}.
+     * Atomically adds the given value to the element at index {@code i},
+     * with memory effects as specified by {@link VarHandle#getAndAdd}.
      *
      * @param i the index
      * @param delta the value to add
      * @return the previous value
      */
     public final int getAndAdd(int i, int delta) {
-        return U.getAndAddInt(array, checkedByteOffset(i), delta);
+        return (int)AA.getAndAdd(array, i, delta);
     }
 
     /**
-     * Atomically increments by one the element at index {@code i}.
+     * Atomically increments the value of the element at index {@code i},
+     * with memory effects as specified by {@link VarHandle#addAndGet}.
+     *
+     * <p>Equivalent to {@code addAndGet(i, 1)}.
      *
      * @param i the index
      * @return the updated value
      */
     public final int incrementAndGet(int i) {
-        return getAndAdd(i, 1) + 1;
+        return (int)AA.addAndGet(array, i, 1);
     }
 
     /**
-     * Atomically decrements by one the element at index {@code i}.
+     * Atomically decrements the value of the element at index {@code i},
+     * with memory effects as specified by {@link VarHandle#addAndGet}.
+     *
+     * <p>Equivalent to {@code addAndGet(i, -1)}.
      *
      * @param i the index
      * @return the updated value
      */
     public final int decrementAndGet(int i) {
-        return getAndAdd(i, -1) - 1;
+        return (int)AA.addAndGet(array, i, -1);
     }
 
     /**
-     * Atomically adds the given value to the element at index {@code i}.
+     * Atomically adds the given value to the element at index {@code i},
+     * with memory effects as specified by {@link VarHandle#addAndGet}.
      *
      * @param i the index
      * @param delta the value to add
      * @return the updated value
      */
     public final int addAndGet(int i, int delta) {
-        return getAndAdd(i, delta) + delta;
+        return (int)AA.addAndGet(array, i, delta);
     }
 
     /**
@@ -260,13 +248,14 @@ public class AtomicIntegerArray implements java.io.Serializable {
      * @since 1.8
      */
     public final int getAndUpdate(int i, IntUnaryOperator updateFunction) {
-        long offset = checkedByteOffset(i);
-        int prev, next;
-        do {
-            prev = getRaw(offset);
-            next = updateFunction.applyAsInt(prev);
-        } while (!compareAndSetRaw(offset, prev, next));
-        return prev;
+        int prev = get(i), next = 0;
+        for (boolean haveNext = false;;) {
+            if (!haveNext)
+                next = updateFunction.applyAsInt(prev);
+            if (weakCompareAndSetVolatile(i, prev, next))
+                return prev;
+            haveNext = (prev == (prev = get(i)));
+        }
     }
 
     /**
@@ -281,23 +270,25 @@ public class AtomicIntegerArray implements java.io.Serializable {
      * @since 1.8
      */
     public final int updateAndGet(int i, IntUnaryOperator updateFunction) {
-        long offset = checkedByteOffset(i);
-        int prev, next;
-        do {
-            prev = getRaw(offset);
-            next = updateFunction.applyAsInt(prev);
-        } while (!compareAndSetRaw(offset, prev, next));
-        return next;
+        int prev = get(i), next = 0;
+        for (boolean haveNext = false;;) {
+            if (!haveNext)
+                next = updateFunction.applyAsInt(prev);
+            if (weakCompareAndSetVolatile(i, prev, next))
+                return next;
+            haveNext = (prev == (prev = get(i)));
+        }
     }
 
     /**
      * Atomically updates the element at index {@code i} with the
-     * results of applying the given function to the current and
-     * given values, returning the previous value. The function should
-     * be side-effect-free, since it may be re-applied when attempted
+     * results of applying the given function to the current and given
+     * values, returning the previous value. The function should be
+     * side-effect-free, since it may be re-applied when attempted
      * updates fail due to contention among threads.  The function is
-     * applied with the current value at index {@code i} as its first
-     * argument, and the given update as the second argument.
+     * applied with the current value of the element at index {@code i}
+     * as its first argument, and the given update as the second
+     * argument.
      *
      * @param i the index
      * @param x the update value
@@ -307,23 +298,25 @@ public class AtomicIntegerArray implements java.io.Serializable {
      */
     public final int getAndAccumulate(int i, int x,
                                       IntBinaryOperator accumulatorFunction) {
-        long offset = checkedByteOffset(i);
-        int prev, next;
-        do {
-            prev = getRaw(offset);
-            next = accumulatorFunction.applyAsInt(prev, x);
-        } while (!compareAndSetRaw(offset, prev, next));
-        return prev;
+        int prev = get(i), next = 0;
+        for (boolean haveNext = false;;) {
+            if (!haveNext)
+                next = accumulatorFunction.applyAsInt(prev, x);
+            if (weakCompareAndSetVolatile(i, prev, next))
+                return prev;
+            haveNext = (prev == (prev = get(i)));
+        }
     }
 
     /**
      * Atomically updates the element at index {@code i} with the
-     * results of applying the given function to the current and
-     * given values, returning the updated value. The function should
-     * be side-effect-free, since it may be re-applied when attempted
+     * results of applying the given function to the current and given
+     * values, returning the updated value. The function should be
+     * side-effect-free, since it may be re-applied when attempted
      * updates fail due to contention among threads.  The function is
-     * applied with the current value at index {@code i} as its first
-     * argument, and the given update as the second argument.
+     * applied with the current value of the element at index {@code i}
+     * as its first argument, and the given update as the second
+     * argument.
      *
      * @param i the index
      * @param x the update value
@@ -333,13 +326,14 @@ public class AtomicIntegerArray implements java.io.Serializable {
      */
     public final int accumulateAndGet(int i, int x,
                                       IntBinaryOperator accumulatorFunction) {
-        long offset = checkedByteOffset(i);
-        int prev, next;
-        do {
-            prev = getRaw(offset);
-            next = accumulatorFunction.applyAsInt(prev, x);
-        } while (!compareAndSetRaw(offset, prev, next));
-        return next;
+        int prev = get(i), next = 0;
+        for (boolean haveNext = false;;) {
+            if (!haveNext)
+                next = accumulatorFunction.applyAsInt(prev, x);
+            if (weakCompareAndSetVolatile(i, prev, next))
+                return next;
+            haveNext = (prev == (prev = get(i)));
+        }
     }
 
     /**
@@ -354,11 +348,190 @@ public class AtomicIntegerArray implements java.io.Serializable {
         StringBuilder b = new StringBuilder();
         b.append('[');
         for (int i = 0; ; i++) {
-            b.append(getRaw(byteOffset(i)));
+            b.append(get(i));
             if (i == iMax)
                 return b.append(']').toString();
             b.append(',').append(' ');
         }
     }
 
+    // jdk9
+
+    /**
+     * Returns the current value of the element at index {@code i},
+     * with memory semantics of reading as if the variable was declared
+     * non-{@code volatile}.
+     *
+     * @param i the index
+     * @return the value
+     * @since 9
+     */
+    public final int getPlain(int i) {
+        return (int)AA.get(array, i);
+    }
+
+    /**
+     * Sets the element at index {@code i} to {@code newValue},
+     * with memory semantics of setting as if the variable was
+     * declared non-{@code volatile} and non-{@code final}.
+     *
+     * @param i the index
+     * @param newValue the new value
+     * @since 9
+     */
+    public final void setPlain(int i, int newValue) {
+        AA.set(array, i, newValue);
+    }
+
+    /**
+     * Returns the current value of the element at index {@code i},
+     * with memory effects as specified by {@link VarHandle#getOpaque}.
+     *
+     * @param i the index
+     * @return the value
+     * @since 9
+     */
+    public final int getOpaque(int i) {
+        return (int)AA.getOpaque(array, i);
+    }
+
+    /**
+     * Sets the element at index {@code i} to {@code newValue},
+     * with memory effects as specified by {@link VarHandle#setOpaque}.
+     *
+     * @param i the index
+     * @param newValue the new value
+     * @since 9
+     */
+    public final void setOpaque(int i, int newValue) {
+        AA.setOpaque(array, i, newValue);
+    }
+
+    /**
+     * Returns the current value of the element at index {@code i},
+     * with memory effects as specified by {@link VarHandle#getAcquire}.
+     *
+     * @param i the index
+     * @return the value
+     * @since 9
+     */
+    public final int getAcquire(int i) {
+        return (int)AA.getAcquire(array, i);
+    }
+
+    /**
+     * Sets the element at index {@code i} to {@code newValue},
+     * with memory effects as specified by {@link VarHandle#setRelease}.
+     *
+     * @param i the index
+     * @param newValue the new value
+     * @since 9
+     */
+    public final void setRelease(int i, int newValue) {
+        AA.setRelease(array, i, newValue);
+    }
+
+    /**
+     * Atomically sets the element at index {@code i} to {@code newValue}
+     * if the element's current value, referred to as the <em>witness
+     * value</em>, {@code == expectedValue},
+     * with memory effects as specified by
+     * {@link VarHandle#compareAndExchange}.
+     *
+     * @param i the index
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return the witness value, which will be the same as the
+     * expected value if successful
+     * @since 9
+     */
+    public final int compareAndExchange(int i, int expectedValue, int newValue) {
+        return (int)AA.compareAndExchange(array, i, expectedValue, newValue);
+    }
+
+    /**
+     * Atomically sets the element at index {@code i} to {@code newValue}
+     * if the element's current value, referred to as the <em>witness
+     * value</em>, {@code == expectedValue},
+     * with memory effects as specified by
+     * {@link VarHandle#compareAndExchangeAcquire}.
+     *
+     * @param i the index
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return the witness value, which will be the same as the
+     * expected value if successful
+     * @since 9
+     */
+    public final int compareAndExchangeAcquire(int i, int expectedValue, int newValue) {
+        return (int)AA.compareAndExchangeAcquire(array, i, expectedValue, newValue);
+    }
+
+    /**
+     * Atomically sets the element at index {@code i} to {@code newValue}
+     * if the element's current value, referred to as the <em>witness
+     * value</em>, {@code == expectedValue},
+     * with memory effects as specified by
+     * {@link VarHandle#compareAndExchangeRelease}.
+     *
+     * @param i the index
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return the witness value, which will be the same as the
+     * expected value if successful
+     * @since 9
+     */
+    public final int compareAndExchangeRelease(int i, int expectedValue, int newValue) {
+        return (int)AA.compareAndExchangeRelease(array, i, expectedValue, newValue);
+    }
+
+    /**
+     * Possibly atomically sets the element at index {@code i} to
+     * {@code newValue} if the element's current value {@code == expectedValue},
+     * with memory effects as specified by
+     * {@link VarHandle#weakCompareAndSetVolatile}.
+     *
+     * @param i the index
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return {@code true} if successful
+     * @since 9
+     */
+    public final boolean weakCompareAndSetVolatile(int i, int expectedValue, int newValue) {
+        return AA.weakCompareAndSetVolatile(array, i, expectedValue, newValue);
+    }
+
+    /**
+     * Possibly atomically sets the element at index {@code i} to
+     * {@code newValue} if the element's current value {@code == expectedValue},
+     * with memory effects as specified by
+     * {@link VarHandle#weakCompareAndSetAcquire}.
+     *
+     * @param i the index
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return {@code true} if successful
+     * @since 9
+     */
+    public final boolean weakCompareAndSetAcquire(int i, int expectedValue, int newValue) {
+        return AA.weakCompareAndSetAcquire(array, i, expectedValue, newValue);
+    }
+
+    /**
+     * Possibly atomically sets the element at index {@code i} to
+     * {@code newValue} if the element's current value {@code == expectedValue},
+     * with memory effects as specified by
+     * {@link VarHandle#weakCompareAndSetRelease}.
+     *
+     * @param i the index
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return {@code true} if successful
+     * @since 9
+     */
+    public final boolean weakCompareAndSetRelease(int i, int expectedValue, int newValue) {
+        return AA.weakCompareAndSetRelease(array, i, expectedValue, newValue);
+    }
+
+
 }

jdk/src/java.base/share/classes/java/util/concurrent/atomic/AtomicIntegerFieldUpdater.java

@@ -42,6 +42,7 @@ import java.security.PrivilegedActionException;
 import java.security.PrivilegedExceptionAction;
 import java.util.function.IntBinaryOperator;
 import java.util.function.IntUnaryOperator;
+import jdk.internal.misc.Unsafe;
 import jdk.internal.reflect.CallerSensitive;
 import jdk.internal.reflect.Reflection;
 
@@ -150,8 +151,8 @@ public abstract class AtomicIntegerFieldUpdater<T> {
     public abstract void lazySet(T obj, int newValue);
 
     /**
-     * Gets the current value held in the field of the given object managed
-     * by this updater.
+     * Returns the current value held in the field of the given object
+     * managed by this updater.
      *
      * @param obj An object whose field to get
      * @return the current value
@@ -367,7 +368,7 @@ public abstract class AtomicIntegerFieldUpdater<T> {
      */
     private static final class AtomicIntegerFieldUpdaterImpl<T>
         extends AtomicIntegerFieldUpdater<T> {
-        private static final jdk.internal.misc.Unsafe U = jdk.internal.misc.Unsafe.getUnsafe();
+        private static final Unsafe U = Unsafe.getUnsafe();
         private final long offset;
         /**
          * if field is protected, the subclass constructing updater, else

jdk/src/java.base/share/classes/java/util/concurrent/atomic/AtomicLong.java

@@ -35,31 +35,30 @@
 
 package java.util.concurrent.atomic;
 
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.VarHandle;
 import java.util.function.LongBinaryOperator;
 import java.util.function.LongUnaryOperator;
 
 /**
  * A {@code long} value that may be updated atomically.  See the
- * {@link java.util.concurrent.atomic} package specification for
- * description of the properties of atomic variables. An
- * {@code AtomicLong} is used in applications such as atomically
- * incremented sequence numbers, and cannot be used as a replacement
- * for a {@link java.lang.Long}. However, this class does extend
- * {@code Number} to allow uniform access by tools and utilities that
- * deal with numerically-based classes.
+ * {@link VarHandle} specification for descriptions of the properties
+ * of atomic accesses. An {@code AtomicLong} is used in applications
+ * such as atomically incremented sequence numbers, and cannot be used
+ * as a replacement for a {@link java.lang.Long}. However, this class
+ * does extend {@code Number} to allow uniform access by tools and
+ * utilities that deal with numerically-based classes.
  *
  * @since 1.5
  * @author Doug Lea
  */
 public class AtomicLong extends Number implements java.io.Serializable {
     private static final long serialVersionUID = 1927816293512124184L;
-
-    private static final jdk.internal.misc.Unsafe U = jdk.internal.misc.Unsafe.getUnsafe();
-    private static final long VALUE;
+    private static final VarHandle VALUE;
 
     /**
      * Records whether the underlying JVM supports lockless
-     * compareAndSwap for longs. While the Unsafe.compareAndSwapLong
+     * compareAndSwap for longs. While the intrinsic compareAndSwapLong
      * method works in either case, some constructions should be
      * handled at Java level to avoid locking user-visible locks.
      */
@@ -73,8 +72,8 @@ public class AtomicLong extends Number implements java.io.Serializable {
 
     static {
         try {
-            VALUE = U.objectFieldOffset
-                (AtomicLong.class.getDeclaredField("value"));
+            MethodHandles.Lookup l = MethodHandles.lookup();
+            VALUE = l.findVarHandle(AtomicLong.class, "value", long.class);
         } catch (ReflectiveOperationException e) {
             throw new Error(e);
         }
@@ -98,7 +97,8 @@ public class AtomicLong extends Number implements java.io.Serializable {
     }
 
     /**
-     * Gets the current value.
+     * Returns the current value,
+     * with memory effects as specified by {@link VarHandle#getVolatile}.
      *
      * @return the current value
      */
@@ -107,119 +107,132 @@ public class AtomicLong extends Number implements java.io.Serializable {
     }
 
     /**
-     * Sets to the given value.
+     * Sets the value to {@code newValue},
+     * with memory effects as specified by {@link VarHandle#setVolatile}.
      *
      * @param newValue the new value
      */
     public final void set(long newValue) {
-        // Use putLongVolatile instead of ordinary volatile store when
-        // using compareAndSwapLong, for sake of some 32bit systems.
-        U.putLongVolatile(this, VALUE, newValue);
+        VALUE.setVolatile(this, newValue);
     }
 
     /**
-     * Eventually sets to the given value.
+     * Sets the value to {@code newValue},
+     * with memory effects as specified by {@link VarHandle#setRelease}.
      *
      * @param newValue the new value
      * @since 1.6
      */
     public final void lazySet(long newValue) {
-        U.putLongRelease(this, VALUE, newValue);
+        VALUE.setRelease(this, newValue);
     }
 
     /**
-     * Atomically sets to the given value and returns the old value.
+     * Atomically sets the value to {@code newValue} and returns the old value,
+     * with memory effects as specified by {@link VarHandle#getAndSet}.
      *
      * @param newValue the new value
      * @return the previous value
      */
     public final long getAndSet(long newValue) {
-        return U.getAndSetLong(this, VALUE, newValue);
+        return (long)VALUE.getAndSet(this, newValue);
     }
 
     /**
-     * Atomically sets the value to the given updated value
-     * if the current value {@code ==} the expected value.
+     * Atomically sets the value to {@code newValue}
+     * if the current value {@code == expectedValue},
+     * with memory effects as specified by {@link VarHandle#compareAndSet}.
      *
-     * @param expect the expected value
-     * @param update the new value
+     * @param expectedValue the expected value
+     * @param newValue the new value
      * @return {@code true} if successful. False return indicates that
      * the actual value was not equal to the expected value.
      */
-    public final boolean compareAndSet(long expect, long update) {
-        return U.compareAndSwapLong(this, VALUE, expect, update);
+    public final boolean compareAndSet(long expectedValue, long newValue) {
+        return VALUE.compareAndSet(this, expectedValue, newValue);
     }
 
     /**
-     * Atomically sets the value to the given updated value
-     * if the current value {@code ==} the expected value.
+     * Possibly atomically sets the value to {@code newValue}
+     * if the current value {@code == expectedValue},
+     * with memory effects as specified by {@link VarHandle#weakCompareAndSet}.
      *
-     * <p><a href="package-summary.html#weakCompareAndSet">May fail
-     * spuriously and does not provide ordering guarantees</a>, so is
-     * only rarely an appropriate alternative to {@code compareAndSet}.
-     *
-     * @param expect the expected value
-     * @param update the new value
+     * @param expectedValue the expected value
+     * @param newValue the new value
      * @return {@code true} if successful
      */
-    public final boolean weakCompareAndSet(long expect, long update) {
-        return U.compareAndSwapLong(this, VALUE, expect, update);
+    public final boolean weakCompareAndSet(long expectedValue, long newValue) {
+        return VALUE.weakCompareAndSet(this, expectedValue, newValue);
     }
 
     /**
-     * Atomically increments by one the current value.
+     * Atomically increments the current value,
+     * with memory effects as specified by {@link VarHandle#getAndAdd}.
+     *
+     * <p>Equivalent to {@code getAndAdd(1)}.
      *
      * @return the previous value
      */
     public final long getAndIncrement() {
-        return U.getAndAddLong(this, VALUE, 1L);
+        return (long)VALUE.getAndAdd(this, 1L);
     }
 
     /**
-     * Atomically decrements by one the current value.
+     * Atomically decrements the current value,
+     * with memory effects as specified by {@link VarHandle#getAndAdd}.
+     *
+     * <p>Equivalent to {@code getAndAdd(-1)}.
      *
      * @return the previous value
      */
     public final long getAndDecrement() {
-        return U.getAndAddLong(this, VALUE, -1L);
+        return (long)VALUE.getAndAdd(this, -1L);
     }
 
     /**
-     * Atomically adds the given value to the current value.
+     * Atomically adds the given value to the current value,
+     * with memory effects as specified by {@link VarHandle#getAndAdd}.
      *
      * @param delta the value to add
      * @return the previous value
      */
     public final long getAndAdd(long delta) {
-        return U.getAndAddLong(this, VALUE, delta);
+        return (long)VALUE.getAndAdd(this, delta);
     }
 
     /**
-     * Atomically increments by one the current value.
+     * Atomically increments the current value,
+     * with memory effects as specified by {@link VarHandle#addAndGet}.
+     *
+     * <p>Equivalent to {@code addAndGet(1)}.
      *
      * @return the updated value
      */
     public final long incrementAndGet() {
-        return U.getAndAddLong(this, VALUE, 1L) + 1L;
+        return (long)VALUE.addAndGet(this, 1L);
     }
 
     /**
-     * Atomically decrements by one the current value.
+     * Atomically decrements the current value,
+     * with memory effects as specified by {@link VarHandle#addAndGet}.
+     *
+     * <p>Equivalent to {@code addAndGet(-1)}.
      *
      * @return the updated value
      */
     public final long decrementAndGet() {
-        return U.getAndAddLong(this, VALUE, -1L) - 1L;
+        return (long)VALUE.addAndGet(this, -1L);
     }
 
     /**
-     * Atomically adds the given value to the current value.
+     * Atomically adds the given value to the current value,
+     * with memory effects as specified by {@link VarHandle#addAndGet}.
      *
      * @param delta the value to add
      * @return the updated value
      */
     public final long addAndGet(long delta) {
-        return U.getAndAddLong(this, VALUE, delta) + delta;
+        return (long)VALUE.addAndGet(this, delta);
     }
 
     /**
@@ -233,12 +246,14 @@ public class AtomicLong extends Number implements java.io.Serializable {
      * @since 1.8
      */
     public final long getAndUpdate(LongUnaryOperator updateFunction) {
-        long prev, next;
-        do {
-            prev = get();
-            next = updateFunction.applyAsLong(prev);
-        } while (!compareAndSet(prev, next));
-        return prev;
+        long prev = get(), next = 0L;
+        for (boolean haveNext = false;;) {
+            if (!haveNext)
+                next = updateFunction.applyAsLong(prev);
+            if (weakCompareAndSetVolatile(prev, next))
+                return prev;
+            haveNext = (prev == (prev = get()));
+        }
     }
 
     /**
@@ -252,12 +267,14 @@ public class AtomicLong extends Number implements java.io.Serializable {
      * @since 1.8
      */
     public final long updateAndGet(LongUnaryOperator updateFunction) {
-        long prev, next;
-        do {
-            prev = get();
-            next = updateFunction.applyAsLong(prev);
-        } while (!compareAndSet(prev, next));
-        return next;
+        long prev = get(), next = 0L;
+        for (boolean haveNext = false;;) {
+            if (!haveNext)
+                next = updateFunction.applyAsLong(prev);
+            if (weakCompareAndSetVolatile(prev, next))
+                return next;
+            haveNext = (prev == (prev = get()));
+        }
     }
 
     /**
@@ -276,12 +293,14 @@ public class AtomicLong extends Number implements java.io.Serializable {
      */
     public final long getAndAccumulate(long x,
                                        LongBinaryOperator accumulatorFunction) {
-        long prev, next;
-        do {
-            prev = get();
-            next = accumulatorFunction.applyAsLong(prev, x);
-        } while (!compareAndSet(prev, next));
-        return prev;
+        long prev = get(), next = 0L;
+        for (boolean haveNext = false;;) {
+            if (!haveNext)
+                next = accumulatorFunction.applyAsLong(prev, x);
+            if (weakCompareAndSetVolatile(prev, next))
+                return prev;
+            haveNext = (prev == (prev = get()));
+        }
     }
 
     /**
@@ -300,12 +319,14 @@ public class AtomicLong extends Number implements java.io.Serializable {
      */
     public final long accumulateAndGet(long x,
                                        LongBinaryOperator accumulatorFunction) {
-        long prev, next;
-        do {
-            prev = get();
-            next = accumulatorFunction.applyAsLong(prev, x);
-        } while (!compareAndSet(prev, next));
-        return next;
+        long prev = get(), next = 0L;
+        for (boolean haveNext = false;;) {
+            if (!haveNext)
+                next = accumulatorFunction.applyAsLong(prev, x);
+            if (weakCompareAndSetVolatile(prev, next))
+                return next;
+            haveNext = (prev == (prev = get()));
+        }
     }
 
     /**
@@ -317,8 +338,9 @@ public class AtomicLong extends Number implements java.io.Serializable {
     }
 
     /**
-     * Returns the value of this {@code AtomicLong} as an {@code int}
-     * after a narrowing primitive conversion.
+     * Returns the current value of this {@code AtomicLong} as an {@code int}
+     * after a narrowing primitive conversion,
+     * with memory effects as specified by {@link VarHandle#getVolatile}.
      * @jls 5.1.3 Narrowing Primitive Conversions
      */
     public int intValue() {
@@ -326,7 +348,8 @@ public class AtomicLong extends Number implements java.io.Serializable {
     }
 
     /**
-     * Returns the value of this {@code AtomicLong} as a {@code long}.
+     * Returns the current value of this {@code AtomicLong} as a {@code long},
+     * with memory effects as specified by {@link VarHandle#getVolatile}.
      * Equivalent to {@link #get()}.
      */
     public long longValue() {
@@ -334,8 +357,9 @@ public class AtomicLong extends Number implements java.io.Serializable {
     }
 
     /**
-     * Returns the value of this {@code AtomicLong} as a {@code float}
-     * after a widening primitive conversion.
+     * Returns the current value of this {@code AtomicLong} as a {@code float}
+     * after a widening primitive conversion,
+     * with memory effects as specified by {@link VarHandle#getVolatile}.
      * @jls 5.1.2 Widening Primitive Conversions
      */
     public float floatValue() {
@@ -343,12 +367,175 @@ public class AtomicLong extends Number implements java.io.Serializable {
     }
 
     /**
-     * Returns the value of this {@code AtomicLong} as a {@code double}
-     * after a widening primitive conversion.
+     * Returns the current value of this {@code AtomicLong} as a {@code double}
+     * after a widening primitive conversion,
+     * with memory effects as specified by {@link VarHandle#getVolatile}.
      * @jls 5.1.2 Widening Primitive Conversions
      */
     public double doubleValue() {
         return (double)get();
     }
 
+    // jdk9
+
+    /**
+     * Returns the current value, with memory semantics of reading as if the
+     * variable was declared non-{@code volatile}.
+     *
+     * @return the value
+     * @since 9
+     */
+    public final long getPlain() {
+        return (long)VALUE.get(this);
+    }
+
+    /**
+     * Sets the value to {@code newValue}, with memory semantics
+     * of setting as if the variable was declared non-{@code volatile}
+     * and non-{@code final}.
+     *
+     * @param newValue the new value
+     * @since 9
+     */
+    public final void setPlain(long newValue) {
+        VALUE.set(this, newValue);
+    }
+
+    /**
+     * Returns the current value,
+     * with memory effects as specified by {@link VarHandle#getOpaque}.
+     *
+     * @return the value
+     * @since 9
+     */
+    public final long getOpaque() {
+        return (long)VALUE.getOpaque(this);
+    }
+
+    /**
+     * Sets the value to {@code newValue},
+     * with memory effects as specified by {@link VarHandle#setOpaque}.
+     *
+     * @param newValue the new value
+     * @since 9
+     */
+    public final void setOpaque(long newValue) {
+        VALUE.setOpaque(this, newValue);
+    }
+
+    /**
+     * Returns the current value,
+     * with memory effects as specified by {@link VarHandle#getAcquire}.
+     *
+     * @return the value
+     * @since 9
+     */
+    public final long getAcquire() {
+        return (long)VALUE.getAcquire(this);
+    }
+
+    /**
+     * Sets the value to {@code newValue},
+     * with memory effects as specified by {@link VarHandle#setRelease}.
+     *
+     * @param newValue the new value
+     * @since 9
+     */
+    public final void setRelease(long newValue) {
+        VALUE.setRelease(this, newValue);
+    }
+
+    /**
+     * Atomically sets the value to {@code newValue} if the current value,
+     * referred to as the <em>witness value</em>, {@code == expectedValue},
+     * with memory effects as specified by
+     * {@link VarHandle#compareAndExchange}.
+     *
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return the witness value, which will be the same as the
+     * expected value if successful
+     * @since 9
+     */
+    public final long compareAndExchange(long expectedValue, long newValue) {
+        return (long)VALUE.compareAndExchange(this, expectedValue, newValue);
+    }
+
+    /**
+     * Atomically sets the value to {@code newValue} if the current value,
+     * referred to as the <em>witness value</em>, {@code == expectedValue},
+     * with memory effects as specified by
+     * {@link VarHandle#compareAndExchangeAcquire}.
+     *
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return the witness value, which will be the same as the
+     * expected value if successful
+     * @since 9
+     */
+    public final long compareAndExchangeAcquire(long expectedValue, long newValue) {
+        return (long)VALUE.compareAndExchangeAcquire(this, expectedValue, newValue);
+    }
+
+    /**
+     * Atomically sets the value to {@code newValue} if the current value,
+     * referred to as the <em>witness value</em>, {@code == expectedValue},
+     * with memory effects as specified by
+     * {@link VarHandle#compareAndExchangeRelease}.
+     *
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return the witness value, which will be the same as the
+     * expected value if successful
+     * @since 9
+     */
+    public final long compareAndExchangeRelease(long expectedValue, long newValue) {
+        return (long)VALUE.compareAndExchangeRelease(this, expectedValue, newValue);
+    }
+
+    /**
+     * Possibly atomically sets the value to {@code newValue}
+     * if the current value {@code == expectedValue},
+     * with memory effects as specified by
+     * {@link VarHandle#weakCompareAndSetVolatile}.
+     *
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return {@code true} if successful
+     * @since 9
+     */
+    public final boolean weakCompareAndSetVolatile(long expectedValue, long newValue) {
+        return VALUE.weakCompareAndSetVolatile(this, expectedValue, newValue);
+    }
+
+    /**
+     * Possibly atomically sets the value to {@code newValue}
+     * if the current value {@code == expectedValue},
+     * with memory effects as specified by
+     * {@link VarHandle#weakCompareAndSetAcquire}.
+     *
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return {@code true} if successful
+     * @since 9
+     */
+    public final boolean weakCompareAndSetAcquire(long expectedValue, long newValue) {
+        return VALUE.weakCompareAndSetAcquire(this, expectedValue, newValue);
+    }
+
+    /**
+     * Possibly atomically sets the value to {@code newValue}
+     * if the current value {@code == expectedValue},
+     * with memory effects as specified by
+     * {@link VarHandle#weakCompareAndSetRelease}.
+     *
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return {@code true} if successful
+     * @since 9
+     */
+    public final boolean weakCompareAndSetRelease(long expectedValue, long newValue) {
+        return VALUE.weakCompareAndSetRelease(this, expectedValue, newValue);
+    }
+
 }

jdk/src/java.base/share/classes/java/util/concurrent/atomic/AtomicLongArray.java

@@ -35,43 +35,24 @@
 
 package java.util.concurrent.atomic;
 
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.VarHandle;
 import java.util.function.LongBinaryOperator;
 import java.util.function.LongUnaryOperator;
 
 /**
  * A {@code long} array in which elements may be updated atomically.
- * See the {@link java.util.concurrent.atomic} package specification
- * for description of the properties of atomic variables.
+ * See the {@link VarHandle} specification for descriptions of the
+ * properties of atomic accesses.
  * @since 1.5
  * @author Doug Lea
  */
 public class AtomicLongArray implements java.io.Serializable {
     private static final long serialVersionUID = -2308431214976778248L;
-
-    private static final jdk.internal.misc.Unsafe U = jdk.internal.misc.Unsafe.getUnsafe();
-    private static final int ABASE;
-    private static final int ASHIFT;
+    private static final VarHandle AA
+        = MethodHandles.arrayElementVarHandle(long[].class);
     private final long[] array;
 
-    static {
-        ABASE = U.arrayBaseOffset(long[].class);
-        int scale = U.arrayIndexScale(long[].class);
-        if ((scale & (scale - 1)) != 0)
-            throw new Error("array index scale not a power of two");
-        ASHIFT = 31 - Integer.numberOfLeadingZeros(scale);
-    }
-
-    private long checkedByteOffset(int i) {
-        if (i < 0 || i >= array.length)
-            throw new IndexOutOfBoundsException("index " + i);
-
-        return byteOffset(i);
-    }
-
-    private static long byteOffset(int i) {
-        return ((long) i << ASHIFT) + ABASE;
-    }
-
     /**
      * Creates a new AtomicLongArray of the given length, with all
      * elements initially zero.
@@ -104,147 +85,155 @@ public class AtomicLongArray implements java.io.Serializable {
     }
 
     /**
-     * Gets the current value at position {@code i}.
+     * Returns the current value of the element at index {@code i},
+     * with memory effects as specified by {@link VarHandle#getVolatile}.
      *
      * @param i the index
      * @return the current value
      */
     public final long get(int i) {
-        return getRaw(checkedByteOffset(i));
-    }
-
-    private long getRaw(long offset) {
-        return U.getLongVolatile(array, offset);
+        return (long)AA.getVolatile(array, i);
     }
 
     /**
-     * Sets the element at position {@code i} to the given value.
+     * Sets the element at index {@code i} to {@code newValue},
+     * with memory effects as specified by {@link VarHandle#setVolatile}.
      *
      * @param i the index
      * @param newValue the new value
      */
     public final void set(int i, long newValue) {
-        U.putLongVolatile(array, checkedByteOffset(i), newValue);
+        AA.setVolatile(array, i, newValue);
     }
 
     /**
-     * Eventually sets the element at position {@code i} to the given value.
+     * Sets the element at index {@code i} to {@code newValue},
+     * with memory effects as specified by {@link VarHandle#setRelease}.
      *
      * @param i the index
      * @param newValue the new value
      * @since 1.6
      */
     public final void lazySet(int i, long newValue) {
-        U.putLongRelease(array, checkedByteOffset(i), newValue);
+        AA.setRelease(array, i, newValue);
     }
 
     /**
-     * Atomically sets the element at position {@code i} to the given value
-     * and returns the old value.
+     * Atomically sets the element at index {@code i} to {@code
+     * newValue} and returns the old value,
+     * with memory effects as specified by {@link VarHandle#getAndSet}.
      *
      * @param i the index
      * @param newValue the new value
      * @return the previous value
      */
     public final long getAndSet(int i, long newValue) {
-        return U.getAndSetLong(array, checkedByteOffset(i), newValue);
+        return (long)AA.getAndSet(array, i, newValue);
     }
 
     /**
-     * Atomically sets the element at position {@code i} to the given
-     * updated value if the current value {@code ==} the expected value.
+     * Atomically sets the element at index {@code i} to {@code newValue}
+     * if the element's current value {@code == expectedValue},
+     * with memory effects as specified by {@link VarHandle#compareAndSet}.
      *
      * @param i the index
-     * @param expect the expected value
-     * @param update the new value
+     * @param expectedValue the expected value
+     * @param newValue the new value
      * @return {@code true} if successful. False return indicates that
      * the actual value was not equal to the expected value.
      */
-    public final boolean compareAndSet(int i, long expect, long update) {
-        return compareAndSetRaw(checkedByteOffset(i), expect, update);
-    }
-
-    private boolean compareAndSetRaw(long offset, long expect, long update) {
-        return U.compareAndSwapLong(array, offset, expect, update);
+    public final boolean compareAndSet(int i, long expectedValue, long newValue) {
+        return AA.compareAndSet(array, i, expectedValue, newValue);
     }
 
     /**
-     * Atomically sets the element at position {@code i} to the given
-     * updated value if the current value {@code ==} the expected value.
-     *
-     * <p><a href="package-summary.html#weakCompareAndSet">May fail
-     * spuriously and does not provide ordering guarantees</a>, so is
-     * only rarely an appropriate alternative to {@code compareAndSet}.
+     * Possibly atomically sets the element at index {@code i} to
+     * {@code newValue} if the element's current value {@code == expectedValue},
+     * with memory effects as specified by {@link VarHandle#weakCompareAndSet}.
      *
      * @param i the index
-     * @param expect the expected value
-     * @param update the new value
+     * @param expectedValue the expected value
+     * @param newValue the new value
      * @return {@code true} if successful
      */
-    public final boolean weakCompareAndSet(int i, long expect, long update) {
-        return compareAndSet(i, expect, update);
+    public final boolean weakCompareAndSet(int i, long expectedValue, long newValue) {
+        return AA.weakCompareAndSet(array, i, expectedValue, newValue);
     }
 
     /**
-     * Atomically increments by one the element at index {@code i}.
+     * Atomically increments the value of the element at index {@code i},
+     * with memory effects as specified by {@link VarHandle#getAndAdd}.
+     *
+     * <p>Equivalent to {@code getAndAdd(i, 1)}.
      *
      * @param i the index
      * @return the previous value
      */
     public final long getAndIncrement(int i) {
-        return getAndAdd(i, 1);
+        return (long)AA.getAndAdd(array, i, 1L);
     }
 
     /**
-     * Atomically decrements by one the element at index {@code i}.
+     * Atomically decrements the value of the element at index {@code i},
+     * with memory effects as specified by {@link VarHandle#getAndAdd}.
+     *
+     * <p>Equivalent to {@code getAndAdd(i, -1)}.
      *
      * @param i the index
      * @return the previous value
      */
     public final long getAndDecrement(int i) {
-        return getAndAdd(i, -1);
+        return (long)AA.getAndAdd(array, i, -1L);
     }
 
     /**
-     * Atomically adds the given value to the element at index {@code i}.
+     * Atomically adds the given value to the element at index {@code i},
+     * with memory effects as specified by {@link VarHandle#getAndAdd}.
      *
      * @param i the index
      * @param delta the value to add
      * @return the previous value
      */
     public final long getAndAdd(int i, long delta) {
-        return U.getAndAddLong(array, checkedByteOffset(i), delta);
+        return (long)AA.getAndAdd(array, i, delta);
     }
 
     /**
-     * Atomically increments by one the element at index {@code i}.
+     * Atomically increments the value of the element at index {@code i},
+     * with memory effects as specified by {@link VarHandle#addAndGet}.
+     *
+     * <p>Equivalent to {@code addAndGet(i, 1)}.
      *
      * @param i the index
      * @return the updated value
      */
     public final long incrementAndGet(int i) {
-        return getAndAdd(i, 1) + 1;
+        return (long)AA.addAndGet(array, i, 1L);
     }
 
     /**
-     * Atomically decrements by one the element at index {@code i}.
+     * Atomically decrements the value of the element at index {@code i},
+     * with memory effects as specified by {@link VarHandle#addAndGet}.
+     *
+     * <p>Equivalent to {@code addAndGet(i, -1)}.
      *
      * @param i the index
      * @return the updated value
      */
     public final long decrementAndGet(int i) {
-        return getAndAdd(i, -1) - 1;
+        return (long)AA.addAndGet(array, i, -1L);
     }
 
     /**
-     * Atomically adds the given value to the element at index {@code i}.
+     * Atomically adds the given value to the element at index {@code i},
+     * with memory effects as specified by {@link VarHandle#addAndGet}.
      *
      * @param i the index
      * @param delta the value to add
      * @return the updated value
      */
     public long addAndGet(int i, long delta) {
-        return getAndAdd(i, delta) + delta;
+        return (long)AA.addAndGet(array, i, delta);
     }
 
     /**
@@ -259,13 +248,14 @@ public class AtomicLongArray implements java.io.Serializable {
      * @since 1.8
      */
     public final long getAndUpdate(int i, LongUnaryOperator updateFunction) {
-        long offset = checkedByteOffset(i);
-        long prev, next;
-        do {
-            prev = getRaw(offset);
-            next = updateFunction.applyAsLong(prev);
-        } while (!compareAndSetRaw(offset, prev, next));
-        return prev;
+        long prev = get(i), next = 0L;
+        for (boolean haveNext = false;;) {
+            if (!haveNext)
+                next = updateFunction.applyAsLong(prev);
+            if (weakCompareAndSetVolatile(i, prev, next))
+                return prev;
+            haveNext = (prev == (prev = get(i)));
+        }
     }
 
     /**
@@ -280,23 +270,25 @@ public class AtomicLongArray implements java.io.Serializable {
      * @since 1.8
      */
     public final long updateAndGet(int i, LongUnaryOperator updateFunction) {
-        long offset = checkedByteOffset(i);
-        long prev, next;
-        do {
-            prev = getRaw(offset);
-            next = updateFunction.applyAsLong(prev);
-        } while (!compareAndSetRaw(offset, prev, next));
-        return next;
+        long prev = get(i), next = 0L;
+        for (boolean haveNext = false;;) {
+            if (!haveNext)
+                next = updateFunction.applyAsLong(prev);
+            if (weakCompareAndSetVolatile(i, prev, next))
+                return next;
+            haveNext = (prev == (prev = get(i)));
+        }
     }
 
     /**
      * Atomically updates the element at index {@code i} with the
-     * results of applying the given function to the current and
-     * given values, returning the previous value. The function should
-     * be side-effect-free, since it may be re-applied when attempted
+     * results of applying the given function to the current and given
+     * values, returning the previous value. The function should be
+     * side-effect-free, since it may be re-applied when attempted
      * updates fail due to contention among threads.  The function is
-     * applied with the current value at index {@code i} as its first
-     * argument, and the given update as the second argument.
+     * applied with the current value of the element at index {@code i}
+     * as its first argument, and the given update as the second
+     * argument.
      *
      * @param i the index
      * @param x the update value
@@ -306,23 +298,25 @@ public class AtomicLongArray implements java.io.Serializable {
      */
     public final long getAndAccumulate(int i, long x,
                                       LongBinaryOperator accumulatorFunction) {
-        long offset = checkedByteOffset(i);
-        long prev, next;
-        do {
-            prev = getRaw(offset);
-            next = accumulatorFunction.applyAsLong(prev, x);
-        } while (!compareAndSetRaw(offset, prev, next));
-        return prev;
+        long prev = get(i), next = 0L;
+        for (boolean haveNext = false;;) {
+            if (!haveNext)
+                next = accumulatorFunction.applyAsLong(prev, x);
+            if (weakCompareAndSetVolatile(i, prev, next))
+                return prev;
+            haveNext = (prev == (prev = get(i)));
+        }
     }
 
     /**
      * Atomically updates the element at index {@code i} with the
-     * results of applying the given function to the current and
-     * given values, returning the updated value. The function should
-     * be side-effect-free, since it may be re-applied when attempted
+     * results of applying the given function to the current and given
+     * values, returning the updated value. The function should be
+     * side-effect-free, since it may be re-applied when attempted
      * updates fail due to contention among threads.  The function is
-     * applied with the current value at index {@code i} as its first
-     * argument, and the given update as the second argument.
+     * applied with the current value of the element at index {@code i}
+     * as its first argument, and the given update as the second
+     * argument.
      *
      * @param i the index
      * @param x the update value
@@ -332,13 +326,14 @@ public class AtomicLongArray implements java.io.Serializable {
      */
     public final long accumulateAndGet(int i, long x,
                                       LongBinaryOperator accumulatorFunction) {
-        long offset = checkedByteOffset(i);
-        long prev, next;
-        do {
-            prev = getRaw(offset);
-            next = accumulatorFunction.applyAsLong(prev, x);
-        } while (!compareAndSetRaw(offset, prev, next));
-        return next;
+        long prev = get(i), next = 0L;
+        for (boolean haveNext = false;;) {
+            if (!haveNext)
+                next = accumulatorFunction.applyAsLong(prev, x);
+            if (weakCompareAndSetVolatile(i, prev, next))
+                return next;
+            haveNext = (prev == (prev = get(i)));
+        }
     }
 
     /**
@@ -353,11 +348,189 @@ public class AtomicLongArray implements java.io.Serializable {
         StringBuilder b = new StringBuilder();
         b.append('[');
         for (int i = 0; ; i++) {
-            b.append(getRaw(byteOffset(i)));
+            b.append(get(i));
             if (i == iMax)
                 return b.append(']').toString();
             b.append(',').append(' ');
         }
     }
 
+    // jdk9
+
+    /**
+     * Returns the current value of the element at index {@code i},
+     * with memory semantics of reading as if the variable was declared
+     * non-{@code volatile}.
+     *
+     * @param i the index
+     * @return the value
+     * @since 9
+     */
+    public final long getPlain(int i) {
+        return (long)AA.get(array, i);
+    }
+
+    /**
+     * Sets the element at index {@code i} to {@code newValue},
+     * with memory semantics of setting as if the variable was
+     * declared non-{@code volatile} and non-{@code final}.
+     *
+     * @param i the index
+     * @param newValue the new value
+     * @since 9
+     */
+    public final void setPlain(int i, long newValue) {
+        AA.set(array, i, newValue);
+    }
+
+    /**
+     * Returns the current value of the element at index {@code i},
+     * with memory effects as specified by {@link VarHandle#getOpaque}.
+     *
+     * @param i the index
+     * @return the value
+     * @since 9
+     */
+    public final long getOpaque(int i) {
+        return (long)AA.getOpaque(array, i);
+    }
+
+    /**
+     * Sets the element at index {@code i} to {@code newValue},
+     * with memory effects as specified by {@link VarHandle#setOpaque}.
+     *
+     * @param i the index
+     * @param newValue the new value
+     * @since 9
+     */
+    public final void setOpaque(int i, long newValue) {
+        AA.setOpaque(array, i, newValue);
+    }
+
+    /**
+     * Returns the current value of the element at index {@code i},
+     * with memory effects as specified by {@link VarHandle#getAcquire}.
+     *
+     * @param i the index
+     * @return the value
+     * @since 9
+     */
+    public final long getAcquire(int i) {
+        return (long)AA.getAcquire(array, i);
+    }
+
+    /**
+     * Sets the element at index {@code i} to {@code newValue},
+     * with memory effects as specified by {@link VarHandle#setRelease}.
+     *
+     * @param i the index
+     * @param newValue the new value
+     * @since 9
+     */
+    public final void setRelease(int i, long newValue) {
+        AA.setRelease(array, i, newValue);
+    }
+
+    /**
+     * Atomically sets the element at index {@code i} to {@code newValue}
+     * if the element's current value, referred to as the <em>witness
+     * value</em>, {@code == expectedValue},
+     * with memory effects as specified by
+     * {@link VarHandle#compareAndExchange}.
+     *
+     * @param i the index
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return the witness value, which will be the same as the
+     * expected value if successful
+     * @since 9
+     */
+    public final long compareAndExchange(int i, long expectedValue, long newValue) {
+        return (long)AA.compareAndExchange(array, i, expectedValue, newValue);
+    }
+
+    /**
+     * Atomically sets the element at index {@code i} to {@code newValue}
+     * if the element's current value, referred to as the <em>witness
+     * value</em>, {@code == expectedValue},
+     * with memory effects as specified by
+     * {@link VarHandle#compareAndExchangeAcquire}.
+     *
+     * @param i the index
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return the witness value, which will be the same as the
+     * expected value if successful
+     * @since 9
+     */
+    public final long compareAndExchangeAcquire(int i, long expectedValue, long newValue) {
+        return (long)AA.compareAndExchangeAcquire(array, i, expectedValue, newValue);
+    }
+
+    /**
+     * Atomically sets the element at index {@code i} to {@code newValue}
+     * if the element's current value, referred to as the <em>witness
+     * value</em>, {@code == expectedValue},
+     * with memory effects as specified by
+     * {@link VarHandle#compareAndExchangeRelease}.
+     *
+     * @param i the index
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return the witness value, which will be the same as the
+     * expected value if successful
+     * @since 9
+     */
+    public final long compareAndExchangeRelease(int i, long expectedValue, long newValue) {
+        return (long)AA.compareAndExchangeRelease(array, i, expectedValue, newValue);
+    }
+
+    /**
+     * Possibly atomically sets the element at index {@code i} to
+     * {@code newValue} if the element's current value {@code == expectedValue},
+     * with memory effects as specified by
+     * {@link VarHandle#weakCompareAndSetVolatile}.
+     *
+     * @param i the index
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return {@code true} if successful
+     * @since 9
+     */
+    public final boolean weakCompareAndSetVolatile(int i, long expectedValue, long newValue) {
+        return AA.weakCompareAndSetVolatile(array, i, expectedValue, newValue);
+    }
+
+    /**
+     * Possibly atomically sets the element at index {@code i} to
+     * {@code newValue} if the element's current value {@code == expectedValue},
+     * with memory effects as specified by
+     * {@link VarHandle#weakCompareAndSetAcquire}.
+     *
+     * @param i the index
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return {@code true} if successful
+     * @since 9
+     */
+    public final boolean weakCompareAndSetAcquire(int i, long expectedValue, long newValue) {
+        return AA.weakCompareAndSetAcquire(array, i, expectedValue, newValue);
+    }
+
+    /**
+     * Possibly atomically sets the element at index {@code i} to
+     * {@code newValue} if the element's current value {@code == expectedValue},
+     * with memory effects as specified by
+     * {@link VarHandle#weakCompareAndSetRelease}.
+     *
+     * @param i the index
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return {@code true} if successful
+     * @since 9
+     */
+    public final boolean weakCompareAndSetRelease(int i, long expectedValue, long newValue) {
+        return AA.weakCompareAndSetRelease(array, i, expectedValue, newValue);
+    }
+
 }

jdk/src/java.base/share/classes/java/util/concurrent/atomic/AtomicLongFieldUpdater.java

@@ -42,6 +42,7 @@ import java.security.PrivilegedActionException;
 import java.security.PrivilegedExceptionAction;
 import java.util.function.LongBinaryOperator;
 import java.util.function.LongUnaryOperator;
+import jdk.internal.misc.Unsafe;
 import jdk.internal.reflect.CallerSensitive;
 import jdk.internal.reflect.Reflection;
 
@@ -153,8 +154,8 @@ public abstract class AtomicLongFieldUpdater<T> {
     public abstract void lazySet(T obj, long newValue);
 
     /**
-     * Gets the current value held in the field of the given object managed
-     * by this updater.
+     * Returns the current value held in the field of the given object
+     * managed by this updater.
      *
      * @param obj An object whose field to get
      * @return the current value
@@ -366,7 +367,7 @@ public abstract class AtomicLongFieldUpdater<T> {
     }
 
     private static final class CASUpdater<T> extends AtomicLongFieldUpdater<T> {
-        private static final jdk.internal.misc.Unsafe U = jdk.internal.misc.Unsafe.getUnsafe();
+        private static final Unsafe U = Unsafe.getUnsafe();
         private final long offset;
         /**
          * if field is protected, the subclass constructing updater, else
@@ -497,7 +498,7 @@ public abstract class AtomicLongFieldUpdater<T> {
     }
 
     private static final class LockedUpdater<T> extends AtomicLongFieldUpdater<T> {
-        private static final jdk.internal.misc.Unsafe U = jdk.internal.misc.Unsafe.getUnsafe();
+        private static final Unsafe U = Unsafe.getUnsafe();
         private final long offset;
         /**
          * if field is protected, the subclass constructing updater, else

jdk/src/java.base/share/classes/java/util/concurrent/atomic/AtomicMarkableReference.java

@@ -35,6 +35,9 @@
 
 package java.util.concurrent.atomic;
 
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.VarHandle;
+
 /**
  * An {@code AtomicMarkableReference} maintains an object reference
  * along with a mark bit, that can be updated atomically.
@@ -188,20 +191,19 @@ public class AtomicMarkableReference<V> {
              casPair(current, Pair.of(expectedReference, newMark)));
     }
 
-    // Unsafe mechanics
-
-    private static final jdk.internal.misc.Unsafe U = jdk.internal.misc.Unsafe.getUnsafe();
-    private static final long PAIR;
+    // VarHandle mechanics
+    private static final VarHandle PAIR;
     static {
         try {
-            PAIR = U.objectFieldOffset
-                (AtomicMarkableReference.class.getDeclaredField("pair"));
+            MethodHandles.Lookup l = MethodHandles.lookup();
+            PAIR = l.findVarHandle(AtomicMarkableReference.class, "pair",
+                                   Pair.class);
         } catch (ReflectiveOperationException e) {
             throw new Error(e);
         }
     }
 
     private boolean casPair(Pair<V> cmp, Pair<V> val) {
-        return U.compareAndSwapObject(this, PAIR, cmp, val);
+        return PAIR.compareAndSet(this, cmp, val);
     }
 }

jdk/src/java.base/share/classes/java/util/concurrent/atomic/AtomicReference.java

@@ -35,33 +35,32 @@
 
 package java.util.concurrent.atomic;
 
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.VarHandle;
 import java.util.function.BinaryOperator;
 import java.util.function.UnaryOperator;
 
 /**
- * An object reference that may be updated atomically. See the {@link
- * java.util.concurrent.atomic} package specification for description
- * of the properties of atomic variables.
+ * An object reference that may be updated atomically.  See the {@link
+ * VarHandle} specification for descriptions of the properties of
+ * atomic accesses.
  * @since 1.5
  * @author Doug Lea
  * @param <V> The type of object referred to by this reference
  */
 public class AtomicReference<V> implements java.io.Serializable {
     private static final long serialVersionUID = -1848883965231344442L;
-
-    private static final jdk.internal.misc.Unsafe U = jdk.internal.misc.Unsafe.getUnsafe();
-    private static final long VALUE;
-
+    private static final VarHandle VALUE;
     static {
         try {
-            VALUE = U.objectFieldOffset
-                (AtomicReference.class.getDeclaredField("value"));
+            MethodHandles.Lookup l = MethodHandles.lookup();
+            VALUE = l.findVarHandle(AtomicReference.class, "value", Object.class);
         } catch (ReflectiveOperationException e) {
             throw new Error(e);
         }
     }
 
-    private volatile V value;
+    private volatile Object value;
 
     /**
      * Creates a new AtomicReference with the given initial value.
@@ -79,16 +78,19 @@ public class AtomicReference<V> implements java.io.Serializable {
     }
 
     /**
-     * Gets the current value.
+     * Returns the current value,
+     * with memory effects as specified by {@link VarHandle#getVolatile}.
      *
      * @return the current value
      */
+    @SuppressWarnings("unchecked")
     public final V get() {
-        return value;
+        return (V)value;
     }
 
     /**
-     * Sets to the given value.
+     * Sets the value to {@code newValue},
+     * with memory effects as specified by {@link VarHandle#setVolatile}.
      *
      * @param newValue the new value
      */
@@ -97,52 +99,53 @@ public class AtomicReference<V> implements java.io.Serializable {
     }
 
     /**
-     * Eventually sets to the given value.
+     * Sets the value to {@code newValue},
+     * with memory effects as specified by {@link VarHandle#setRelease}.
      *
      * @param newValue the new value
      * @since 1.6
      */
     public final void lazySet(V newValue) {
-        U.putObjectRelease(this, VALUE, newValue);
+        VALUE.setRelease(this, newValue);
     }
 
     /**
-     * Atomically sets the value to the given updated value
-     * if the current value {@code ==} the expected value.
-     * @param expect the expected value
-     * @param update the new value
+     * Atomically sets the value to {@code newValue}
+     * if the current value {@code == expectedValue},
+     * with memory effects as specified by {@link VarHandle#compareAndSet}.
+     *
+     * @param expectedValue the expected value
+     * @param newValue the new value
      * @return {@code true} if successful. False return indicates that
      * the actual value was not equal to the expected value.
      */
-    public final boolean compareAndSet(V expect, V update) {
-        return U.compareAndSwapObject(this, VALUE, expect, update);
+    public final boolean compareAndSet(V expectedValue, V newValue) {
+        return VALUE.compareAndSet(this, expectedValue, newValue);
     }
 
     /**
-     * Atomically sets the value to the given updated value
-     * if the current value {@code ==} the expected value.
+     * Possibly atomically sets the value to {@code newValue}
+     * if the current value {@code == expectedValue},
+     * with memory effects as specified by {@link VarHandle#weakCompareAndSet}.
      *
-     * <p><a href="package-summary.html#weakCompareAndSet">May fail
-     * spuriously and does not provide ordering guarantees</a>, so is
-     * only rarely an appropriate alternative to {@code compareAndSet}.
-     *
-     * @param expect the expected value
-     * @param update the new value
+     * @param expectedValue the expected value
+     * @param newValue the new value
      * @return {@code true} if successful
      */
-    public final boolean weakCompareAndSet(V expect, V update) {
-        return U.compareAndSwapObject(this, VALUE, expect, update);
+    public final boolean weakCompareAndSet(V expectedValue, V newValue) {
+        return VALUE.weakCompareAndSet(this, expectedValue, newValue);
     }
 
     /**
-     * Atomically sets to the given value and returns the old value.
+     * Atomically sets the value to {@code newValue} and returns the old value,
+     * with memory effects as specified by {@link VarHandle#getAndSet}.
      *
      * @param newValue the new value
      * @return the previous value
      */
     @SuppressWarnings("unchecked")
     public final V getAndSet(V newValue) {
-        return (V)U.getAndSetObject(this, VALUE, newValue);
+        return (V)VALUE.getAndSet(this, newValue);
     }
 
     /**
@@ -156,12 +159,14 @@ public class AtomicReference<V> implements java.io.Serializable {
      * @since 1.8
      */
     public final V getAndUpdate(UnaryOperator<V> updateFunction) {
-        V prev, next;
-        do {
-            prev = get();
-            next = updateFunction.apply(prev);
-        } while (!compareAndSet(prev, next));
-        return prev;
+        V prev = get(), next = null;
+        for (boolean haveNext = false;;) {
+            if (!haveNext)
+                next = updateFunction.apply(prev);
+            if (weakCompareAndSetVolatile(prev, next))
+                return prev;
+            haveNext = (prev == (prev = get()));
+        }
     }
 
     /**
@@ -175,12 +180,14 @@ public class AtomicReference<V> implements java.io.Serializable {
      * @since 1.8
      */
     public final V updateAndGet(UnaryOperator<V> updateFunction) {
-        V prev, next;
-        do {
-            prev = get();
-            next = updateFunction.apply(prev);
-        } while (!compareAndSet(prev, next));
-        return next;
+        V prev = get(), next = null;
+        for (boolean haveNext = false;;) {
+            if (!haveNext)
+                next = updateFunction.apply(prev);
+            if (weakCompareAndSetVolatile(prev, next))
+                return next;
+            haveNext = (prev == (prev = get()));
+        }
     }
 
     /**
@@ -199,12 +206,14 @@ public class AtomicReference<V> implements java.io.Serializable {
      */
     public final V getAndAccumulate(V x,
                                     BinaryOperator<V> accumulatorFunction) {
-        V prev, next;
-        do {
-            prev = get();
-            next = accumulatorFunction.apply(prev, x);
-        } while (!compareAndSet(prev, next));
-        return prev;
+        V prev = get(), next = null;
+        for (boolean haveNext = false;;) {
+            if (!haveNext)
+                next = accumulatorFunction.apply(prev, x);
+            if (weakCompareAndSetVolatile(prev, next))
+                return prev;
+            haveNext = (prev == (prev = get()));
+        }
     }
 
     /**
@@ -223,12 +232,14 @@ public class AtomicReference<V> implements java.io.Serializable {
      */
     public final V accumulateAndGet(V x,
                                     BinaryOperator<V> accumulatorFunction) {
-        V prev, next;
-        do {
-            prev = get();
-            next = accumulatorFunction.apply(prev, x);
-        } while (!compareAndSet(prev, next));
-        return next;
+        V prev = get(), next = null;
+        for (boolean haveNext = false;;) {
+            if (!haveNext)
+                next = accumulatorFunction.apply(prev, x);
+            if (weakCompareAndSetVolatile(prev, next))
+                return next;
+            haveNext = (prev == (prev = get()));
+        }
     }
 
     /**
@@ -239,4 +250,166 @@ public class AtomicReference<V> implements java.io.Serializable {
         return String.valueOf(get());
     }
 
+    // jdk9
+
+    /**
+     * Returns the current value, with memory semantics of reading as
+     * if the variable was declared non-{@code volatile}.
+     *
+     * @return the value
+     * @since 9
+     */
+    public final V getPlain() {
+        return (V)VALUE.get(this);
+    }
+
+    /**
+     * Sets the value to {@code newValue}, with memory semantics
+     * of setting as if the variable was declared non-{@code volatile}
+     * and non-{@code final}.
+     *
+     * @param newValue the new value
+     * @since 9
+     */
+    public final void setPlain(V newValue) {
+        VALUE.set(this, newValue);
+    }
+
+    /**
+     * Returns the current value,
+     * with memory effects as specified by {@link VarHandle#getOpaque}.
+     *
+     * @return the value
+     * @since 9
+     */
+    public final V getOpaque() {
+        return (V)VALUE.getOpaque(this);
+    }
+
+    /**
+     * Sets the value to {@code newValue},
+     * with memory effects as specified by {@link VarHandle#setOpaque}.
+     *
+     * @param newValue the new value
+     * @since 9
+     */
+    public final void setOpaque(V newValue) {
+        VALUE.setOpaque(this, newValue);
+    }
+
+    /**
+     * Returns the current value,
+     * with memory effects as specified by {@link VarHandle#getAcquire}.
+     *
+     * @return the value
+     * @since 9
+     */
+    public final V getAcquire() {
+        return (V)VALUE.getAcquire(this);
+    }
+
+    /**
+     * Sets the value to {@code newValue},
+     * with memory effects as specified by {@link VarHandle#setRelease}.
+     *
+     * @param newValue the new value
+     * @since 9
+     */
+    public final void setRelease(V newValue) {
+        VALUE.setRelease(this, newValue);
+    }
+
+    /**
+     * Atomically sets the value to {@code newValue} if the current value,
+     * referred to as the <em>witness value</em>, {@code == expectedValue},
+     * with memory effects as specified by
+     * {@link VarHandle#compareAndExchange}.
+     *
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return the witness value, which will be the same as the
+     * expected value if successful
+     * @since 9
+     */
+    public final V compareAndExchange(V expectedValue, V newValue) {
+        return (V)VALUE.compareAndExchange(this, expectedValue, newValue);
+    }
+
+    /**
+     * Atomically sets the value to {@code newValue} if the current value,
+     * referred to as the <em>witness value</em>, {@code == expectedValue},
+     * with memory effects as specified by
+     * {@link VarHandle#compareAndExchangeAcquire}.
+     *
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return the witness value, which will be the same as the
+     * expected value if successful
+     * @since 9
+     */
+    public final V compareAndExchangeAcquire(V expectedValue, V newValue) {
+        return (V)VALUE.compareAndExchangeAcquire(this, expectedValue, newValue);
+    }
+
+    /**
+     * Atomically sets the value to {@code newValue} if the current value,
+     * referred to as the <em>witness value</em>, {@code == expectedValue},
+     * with memory effects as specified by
+     * {@link VarHandle#compareAndExchangeRelease}.
+     *
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return the witness value, which will be the same as the
+     * expected value if successful
+     * @since 9
+     */
+    public final V compareAndExchangeRelease(V expectedValue, V newValue) {
+        return (V)VALUE.compareAndExchangeRelease(this, expectedValue, newValue);
+    }
+
+    /**
+     * Possibly atomically sets the value to {@code newValue}
+     * if the current value {@code == expectedValue},
+     * with memory effects as specified by
+     * {@link VarHandle#weakCompareAndSetVolatile}.
+     *
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return {@code true} if successful
+     * @since 9
+     */
+    public final boolean weakCompareAndSetVolatile(V expectedValue, V newValue) {
+        return VALUE.weakCompareAndSetVolatile(this, expectedValue, newValue);
+    }
+
+    /**
+     * Possibly atomically sets the value to {@code newValue}
+     * if the current value {@code == expectedValue},
+     * with memory effects as specified by
+     * {@link VarHandle#weakCompareAndSetAcquire}.
+     *
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return {@code true} if successful
+     * @since 9
+     */
+    public final boolean weakCompareAndSetAcquire(V expectedValue, V newValue) {
+        return VALUE.weakCompareAndSetAcquire(this, expectedValue, newValue);
+    }
+
+    /**
+     * Possibly atomically sets the value to {@code newValue}
+     * if the current value {@code == expectedValue},
+     * with memory effects as specified by
+     * {@link VarHandle#weakCompareAndSetRelease}.
+     *
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return {@code true} if successful
+     * @since 9
+     */
+    public final boolean weakCompareAndSetRelease(V expectedValue, V newValue) {
+        return VALUE.weakCompareAndSetRelease(this, expectedValue, newValue);
+    }
+
 }

jdk/src/java.base/share/classes/java/util/concurrent/atomic/AtomicReferenceArray.java

@@ -35,54 +35,28 @@
 
 package java.util.concurrent.atomic;
 
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.VarHandle;
 import java.lang.reflect.Array;
+import java.lang.reflect.Field;
 import java.util.Arrays;
 import java.util.function.BinaryOperator;
 import java.util.function.UnaryOperator;
 
 /**
  * An array of object references in which elements may be updated
- * atomically.  See the {@link java.util.concurrent.atomic} package
- * specification for description of the properties of atomic
- * variables.
+ * atomically.  See the {@link VarHandle} specification for
+ * descriptions of the properties of atomic accesses.
  * @since 1.5
  * @author Doug Lea
  * @param <E> The base class of elements held in this array
  */
 public class AtomicReferenceArray<E> implements java.io.Serializable {
     private static final long serialVersionUID = -6209656149925076980L;
-
-    private static final jdk.internal.misc.Unsafe U = jdk.internal.misc.Unsafe.getUnsafe();
-    private static final long ARRAY;
-    private static final int ABASE;
-    private static final int ASHIFT;
+    private static final VarHandle AA
+        = MethodHandles.arrayElementVarHandle(Object[].class);
     private final Object[] array; // must have exact type Object[]
 
-    static {
-        try {
-            ARRAY = U.objectFieldOffset
-                (AtomicReferenceArray.class.getDeclaredField("array"));
-            ABASE = U.arrayBaseOffset(Object[].class);
-            int scale = U.arrayIndexScale(Object[].class);
-            if ((scale & (scale - 1)) != 0)
-                throw new Error("array index scale not a power of two");
-            ASHIFT = 31 - Integer.numberOfLeadingZeros(scale);
-        } catch (ReflectiveOperationException e) {
-            throw new Error(e);
-        }
-    }
-
-    private long checkedByteOffset(int i) {
-        if (i < 0 || i >= array.length)
-            throw new IndexOutOfBoundsException("index " + i);
-
-        return byteOffset(i);
-    }
-
-    private static long byteOffset(int i) {
-        return ((long) i << ASHIFT) + ABASE;
-    }
-
     /**
      * Creates a new AtomicReferenceArray of the given length, with all
      * elements initially null.
@@ -115,44 +89,44 @@ public class AtomicReferenceArray<E> implements java.io.Serializable {
     }
 
     /**
-     * Gets the current value at position {@code i}.
+     * Returns the current value of the element at index {@code i},
+     * with memory effects as specified by {@link VarHandle#getVolatile}.
      *
      * @param i the index
      * @return the current value
      */
-    public final E get(int i) {
-        return getRaw(checkedByteOffset(i));
-    }
-
     @SuppressWarnings("unchecked")
-    private E getRaw(long offset) {
-        return (E) U.getObjectVolatile(array, offset);
+    public final E get(int i) {
+        return (E)AA.getVolatile(array, i);
     }
 
     /**
-     * Sets the element at position {@code i} to the given value.
+     * Sets the element at index {@code i} to {@code newValue},
+     * with memory effects as specified by {@link VarHandle#setVolatile}.
      *
      * @param i the index
      * @param newValue the new value
      */
     public final void set(int i, E newValue) {
-        U.putObjectVolatile(array, checkedByteOffset(i), newValue);
+        AA.setVolatile(array, i, newValue);
     }
 
     /**
-     * Eventually sets the element at position {@code i} to the given value.
+     * Sets the element at index {@code i} to {@code newValue},
+     * with memory effects as specified by {@link VarHandle#setRelease}.
      *
      * @param i the index
      * @param newValue the new value
      * @since 1.6
      */
     public final void lazySet(int i, E newValue) {
-        U.putObjectRelease(array, checkedByteOffset(i), newValue);
+        AA.setRelease(array, i, newValue);
     }
 
     /**
-     * Atomically sets the element at position {@code i} to the given
-     * value and returns the old value.
+     * Atomically sets the element at index {@code i} to {@code
+     * newValue} and returns the old value,
+     * with memory effects as specified by {@link VarHandle#getAndSet}.
      *
      * @param i the index
      * @param newValue the new value
@@ -160,42 +134,36 @@ public class AtomicReferenceArray<E> implements java.io.Serializable {
      */
     @SuppressWarnings("unchecked")
     public final E getAndSet(int i, E newValue) {
-        return (E)U.getAndSetObject(array, checkedByteOffset(i), newValue);
+        return (E)AA.getAndSet(array, i, newValue);
     }
 
     /**
-     * Atomically sets the element at position {@code i} to the given
-     * updated value if the current value {@code ==} the expected value.
+     * Atomically sets the element at index {@code i} to {@code newValue}
+     * if the element's current value {@code == expectedValue},
+     * with memory effects as specified by {@link VarHandle#compareAndSet}.
      *
      * @param i the index
-     * @param expect the expected value
-     * @param update the new value
+     * @param expectedValue the expected value
+     * @param newValue the new value
      * @return {@code true} if successful. False return indicates that
      * the actual value was not equal to the expected value.
      */
-    public final boolean compareAndSet(int i, E expect, E update) {
-        return compareAndSetRaw(checkedByteOffset(i), expect, update);
-    }
-
-    private boolean compareAndSetRaw(long offset, E expect, E update) {
-        return U.compareAndSwapObject(array, offset, expect, update);
+    public final boolean compareAndSet(int i, E expectedValue, E newValue) {
+        return AA.compareAndSet(array, i, expectedValue, newValue);
     }
 
     /**
-     * Atomically sets the element at position {@code i} to the given
-     * updated value if the current value {@code ==} the expected value.
-     *
-     * <p><a href="package-summary.html#weakCompareAndSet">May fail
-     * spuriously and does not provide ordering guarantees</a>, so is
-     * only rarely an appropriate alternative to {@code compareAndSet}.
+     * Possibly atomically sets the element at index {@code i} to
+     * {@code newValue} if the element's current value {@code == expectedValue},
+     * with memory effects as specified by {@link VarHandle#weakCompareAndSet}.
      *
      * @param i the index
-     * @param expect the expected value
-     * @param update the new value
+     * @param expectedValue the expected value
+     * @param newValue the new value
      * @return {@code true} if successful
      */
-    public final boolean weakCompareAndSet(int i, E expect, E update) {
-        return compareAndSet(i, expect, update);
+    public final boolean weakCompareAndSet(int i, E expectedValue, E newValue) {
+        return AA.weakCompareAndSet(array, i, expectedValue, newValue);
     }
 
     /**
@@ -210,13 +178,14 @@ public class AtomicReferenceArray<E> implements java.io.Serializable {
      * @since 1.8
      */
     public final E getAndUpdate(int i, UnaryOperator<E> updateFunction) {
-        long offset = checkedByteOffset(i);
-        E prev, next;
-        do {
-            prev = getRaw(offset);
-            next = updateFunction.apply(prev);
-        } while (!compareAndSetRaw(offset, prev, next));
-        return prev;
+        E prev = get(i), next = null;
+        for (boolean haveNext = false;;) {
+            if (!haveNext)
+                next = updateFunction.apply(prev);
+            if (weakCompareAndSetVolatile(i, prev, next))
+                return prev;
+            haveNext = (prev == (prev = get(i)));
+        }
     }
 
     /**
@@ -231,23 +200,25 @@ public class AtomicReferenceArray<E> implements java.io.Serializable {
      * @since 1.8
      */
     public final E updateAndGet(int i, UnaryOperator<E> updateFunction) {
-        long offset = checkedByteOffset(i);
-        E prev, next;
-        do {
-            prev = getRaw(offset);
-            next = updateFunction.apply(prev);
-        } while (!compareAndSetRaw(offset, prev, next));
-        return next;
+        E prev = get(i), next = null;
+        for (boolean haveNext = false;;) {
+            if (!haveNext)
+                next = updateFunction.apply(prev);
+            if (weakCompareAndSetVolatile(i, prev, next))
+                return next;
+            haveNext = (prev == (prev = get(i)));
+        }
     }
 
     /**
      * Atomically updates the element at index {@code i} with the
-     * results of applying the given function to the current and
-     * given values, returning the previous value. The function should
-     * be side-effect-free, since it may be re-applied when attempted
+     * results of applying the given function to the current and given
+     * values, returning the previous value. The function should be
+     * side-effect-free, since it may be re-applied when attempted
      * updates fail due to contention among threads.  The function is
-     * applied with the current value at index {@code i} as its first
-     * argument, and the given update as the second argument.
+     * applied with the current value of the element at index {@code i}
+     * as its first argument, and the given update as the second
+     * argument.
      *
      * @param i the index
      * @param x the update value
@@ -257,23 +228,25 @@ public class AtomicReferenceArray<E> implements java.io.Serializable {
      */
     public final E getAndAccumulate(int i, E x,
                                     BinaryOperator<E> accumulatorFunction) {
-        long offset = checkedByteOffset(i);
-        E prev, next;
-        do {
-            prev = getRaw(offset);
-            next = accumulatorFunction.apply(prev, x);
-        } while (!compareAndSetRaw(offset, prev, next));
-        return prev;
+        E prev = get(i), next = null;
+        for (boolean haveNext = false;;) {
+            if (!haveNext)
+                next = accumulatorFunction.apply(prev, x);
+            if (weakCompareAndSetVolatile(i, prev, next))
+                return prev;
+            haveNext = (prev == (prev = get(i)));
+        }
     }
 
     /**
      * Atomically updates the element at index {@code i} with the
-     * results of applying the given function to the current and
-     * given values, returning the updated value. The function should
-     * be side-effect-free, since it may be re-applied when attempted
+     * results of applying the given function to the current and given
+     * values, returning the updated value. The function should be
+     * side-effect-free, since it may be re-applied when attempted
      * updates fail due to contention among threads.  The function is
-     * applied with the current value at index {@code i} as its first
-     * argument, and the given update as the second argument.
+     * applied with the current value of the element at index {@code i}
+     * as its first argument, and the given update as the second
+     * argument.
      *
      * @param i the index
      * @param x the update value
@@ -283,13 +256,14 @@ public class AtomicReferenceArray<E> implements java.io.Serializable {
      */
     public final E accumulateAndGet(int i, E x,
                                     BinaryOperator<E> accumulatorFunction) {
-        long offset = checkedByteOffset(i);
-        E prev, next;
-        do {
-            prev = getRaw(offset);
-            next = accumulatorFunction.apply(prev, x);
-        } while (!compareAndSetRaw(offset, prev, next));
-        return next;
+        E prev = get(i), next = null;
+        for (boolean haveNext = false;;) {
+            if (!haveNext)
+                next = accumulatorFunction.apply(prev, x);
+            if (weakCompareAndSetVolatile(i, prev, next))
+                return next;
+            haveNext = (prev == (prev = get(i)));
+        }
     }
 
     /**
@@ -304,7 +278,7 @@ public class AtomicReferenceArray<E> implements java.io.Serializable {
         StringBuilder b = new StringBuilder();
         b.append('[');
         for (int i = 0; ; i++) {
-            b.append(getRaw(byteOffset(i)));
+            b.append(get(i));
             if (i == iMax)
                 return b.append(']').toString();
             b.append(',').append(' ');
@@ -326,7 +300,199 @@ public class AtomicReferenceArray<E> implements java.io.Serializable {
             throw new java.io.InvalidObjectException("Not array type");
         if (a.getClass() != Object[].class)
             a = Arrays.copyOf((Object[])a, Array.getLength(a), Object[].class);
-        U.putObjectVolatile(this, ARRAY, a);
+        Field arrayField = java.security.AccessController.doPrivileged(
+            (java.security.PrivilegedAction<Field>) () -> {
+                try {
+                    Field f = AtomicReferenceArray.class
+                        .getDeclaredField("array");
+                    f.setAccessible(true);
+                    return f;
+                } catch (ReflectiveOperationException e) {
+                    throw new Error(e);
+                }});
+        try {
+            arrayField.set(this, a);
+        } catch (IllegalAccessException e) {
+            throw new Error(e);
+        }
+    }
+
+    // jdk9
+
+    /**
+     * Returns the current value of the element at index {@code i},
+     * with memory semantics of reading as if the variable was declared
+     * non-{@code volatile}.
+     *
+     * @param i the index
+     * @return the value
+     * @since 9
+     */
+    public final E getPlain(int i) {
+        return (E)AA.get(array, i);
+    }
+
+    /**
+     * Sets the element at index {@code i} to {@code newValue},
+     * with memory semantics of setting as if the variable was
+     * declared non-{@code volatile} and non-{@code final}.
+     *
+     * @param i the index
+     * @param newValue the new value
+     * @since 9
+     */
+    public final void setPlain(int i, E newValue) {
+        AA.set(array, i, newValue);
+    }
+
+    /**
+     * Returns the current value of the element at index {@code i},
+     * with memory effects as specified by {@link VarHandle#getOpaque}.
+     *
+     * @param i the index
+     * @return the value
+     * @since 9
+     */
+    public final E getOpaque(int i) {
+        return (E)AA.getOpaque(array, i);
+    }
+
+    /**
+     * Sets the element at index {@code i} to {@code newValue},
+     * with memory effects as specified by {@link VarHandle#setOpaque}.
+     *
+     * @param i the index
+     * @param newValue the new value
+     * @since 9
+     */
+    public final void setOpaque(int i, E newValue) {
+        AA.setOpaque(array, i, newValue);
+    }
+
+    /**
+     * Returns the current value of the element at index {@code i},
+     * with memory effects as specified by {@link VarHandle#getAcquire}.
+     *
+     * @param i the index
+     * @return the value
+     * @since 9
+     */
+    public final E getAcquire(int i) {
+        return (E)AA.getAcquire(array, i);
+    }
+
+    /**
+     * Sets the element at index {@code i} to {@code newValue},
+     * with memory effects as specified by {@link VarHandle#setRelease}.
+     *
+     * @param i the index
+     * @param newValue the new value
+     * @since 9
+     */
+    public final void setRelease(int i, E newValue) {
+        AA.setRelease(array, i, newValue);
+    }
+
+    /**
+     * Atomically sets the element at index {@code i} to {@code newValue}
+     * if the element's current value, referred to as the <em>witness
+     * value</em>, {@code == expectedValue},
+     * with memory effects as specified by
+     * {@link VarHandle#compareAndExchange}.
+     *
+     * @param i the index
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return the witness value, which will be the same as the
+     * expected value if successful
+     * @since 9
+     */
+    public final E compareAndExchange(int i, E expectedValue, E newValue) {
+        return (E)AA.compareAndExchange(array, i, expectedValue, newValue);
+    }
+
+    /**
+     * Atomically sets the element at index {@code i} to {@code newValue}
+     * if the element's current value, referred to as the <em>witness
+     * value</em>, {@code == expectedValue},
+     * with memory effects as specified by
+     * {@link VarHandle#compareAndExchangeAcquire}.
+     *
+     * @param i the index
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return the witness value, which will be the same as the
+     * expected value if successful
+     * @since 9
+     */
+    public final E compareAndExchangeAcquire(int i, E expectedValue, E newValue) {
+        return (E)AA.compareAndExchangeAcquire(array, i, expectedValue, newValue);
+    }
+
+    /**
+     * Atomically sets the element at index {@code i} to {@code newValue}
+     * if the element's current value, referred to as the <em>witness
+     * value</em>, {@code == expectedValue},
+     * with memory effects as specified by
+     * {@link VarHandle#compareAndExchangeRelease}.
+     *
+     * @param i the index
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return the witness value, which will be the same as the
+     * expected value if successful
+     * @since 9
+     */
+    public final E compareAndExchangeRelease(int i, E expectedValue, E newValue) {
+        return (E)AA.compareAndExchangeRelease(array, i, expectedValue, newValue);
+    }
+
+    /**
+     * Possibly atomically sets the element at index {@code i} to
+     * {@code newValue} if the element's current value {@code == expectedValue},
+     * with memory effects as specified by
+     * {@link VarHandle#weakCompareAndSetVolatile}.
+     *
+     * @param i the index
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return {@code true} if successful
+     * @since 9
+     */
+    public final boolean weakCompareAndSetVolatile(int i, E expectedValue, E newValue) {
+        return AA.weakCompareAndSetVolatile(array, i, expectedValue, newValue);
+    }
+
+    /**
+     * Possibly atomically sets the element at index {@code i} to
+     * {@code newValue} if the element's current value {@code == expectedValue},
+     * with memory effects as specified by
+     * {@link VarHandle#weakCompareAndSetAcquire}.
+     *
+     * @param i the index
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return {@code true} if successful
+     * @since 9
+     */
+    public final boolean weakCompareAndSetAcquire(int i, E expectedValue, E newValue) {
+        return AA.weakCompareAndSetAcquire(array, i, expectedValue, newValue);
+    }
+
+    /**
+     * Possibly atomically sets the element at index {@code i} to
+     * {@code newValue} if the element's current value {@code == expectedValue},
+     * with memory effects as specified by
+     * {@link VarHandle#weakCompareAndSetRelease}.
+     *
+     * @param i the index
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return {@code true} if successful
+     * @since 9
+     */
+    public final boolean weakCompareAndSetRelease(int i, E expectedValue, E newValue) {
+        return AA.weakCompareAndSetRelease(array, i, expectedValue, newValue);
     }
 
 }

jdk/src/java.base/share/classes/java/util/concurrent/atomic/AtomicReferenceFieldUpdater.java

@@ -42,6 +42,7 @@ import java.security.PrivilegedActionException;
 import java.security.PrivilegedExceptionAction;
 import java.util.function.BinaryOperator;
 import java.util.function.UnaryOperator;
+import jdk.internal.misc.Unsafe;
 import jdk.internal.reflect.CallerSensitive;
 import jdk.internal.reflect.Reflection;
 
@@ -168,8 +169,8 @@ public abstract class AtomicReferenceFieldUpdater<T,V> {
     public abstract void lazySet(T obj, V newValue);
 
     /**
-     * Gets the current value held in the field of the given object managed
-     * by this updater.
+     * Returns the current value held in the field of the given object
+     * managed by this updater.
      *
      * @param obj An object whose field to get
      * @return the current value
@@ -284,7 +285,7 @@ public abstract class AtomicReferenceFieldUpdater<T,V> {
 
     private static final class AtomicReferenceFieldUpdaterImpl<T,V>
         extends AtomicReferenceFieldUpdater<T,V> {
-        private static final jdk.internal.misc.Unsafe U = jdk.internal.misc.Unsafe.getUnsafe();
+        private static final Unsafe U = Unsafe.getUnsafe();
         private final long offset;
         /**
          * if field is protected, the subclass constructing updater, else

jdk/src/java.base/share/classes/java/util/concurrent/atomic/AtomicStampedReference.java

@@ -35,6 +35,9 @@
 
 package java.util.concurrent.atomic;
 
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.VarHandle;
+
 /**
  * An {@code AtomicStampedReference} maintains an object reference
  * along with an integer "stamp", that can be updated atomically.
@@ -188,20 +191,19 @@ public class AtomicStampedReference<V> {
              casPair(current, Pair.of(expectedReference, newStamp)));
     }
 
-    // Unsafe mechanics
-
-    private static final jdk.internal.misc.Unsafe U = jdk.internal.misc.Unsafe.getUnsafe();
-    private static final long PAIR;
+    // VarHandle mechanics
+    private static final VarHandle PAIR;
     static {
         try {
-            PAIR = U.objectFieldOffset
-                (AtomicStampedReference.class.getDeclaredField("pair"));
+            MethodHandles.Lookup l = MethodHandles.lookup();
+            PAIR = l.findVarHandle(AtomicStampedReference.class, "pair",
+                                   Pair.class);
         } catch (ReflectiveOperationException e) {
             throw new Error(e);
         }
     }
 
     private boolean casPair(Pair<V> cmp, Pair<V> val) {
-        return U.compareAndSwapObject(this, PAIR, cmp, val);
+        return PAIR.compareAndSet(this, cmp, val);
     }
 }

jdk/src/java.base/share/classes/java/util/concurrent/atomic/LongAccumulator.java

@@ -68,7 +68,7 @@ import java.util.function.LongBinaryOperator;
  * <p>Class {@link LongAdder} provides analogs of the functionality of
  * this class for the common special case of maintaining counts and
  * sums.  The call {@code new LongAdder()} is equivalent to {@code new
- * LongAccumulator((x, y) -> x + y, 0L}.
+ * LongAccumulator((x, y) -> x + y, 0L)}.
  *
  * <p>This class extends {@link Number}, but does <em>not</em> define
  * methods such as {@code equals}, {@code hashCode} and {@code

jdk/src/java.base/share/classes/java/util/concurrent/atomic/Striped64.java

@@ -35,10 +35,13 @@
 
 package java.util.concurrent.atomic;
 
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.VarHandle;
 import java.util.Arrays;
 import java.util.concurrent.ThreadLocalRandom;
 import java.util.function.DoubleBinaryOperator;
 import java.util.function.LongBinaryOperator;
+import jdk.internal.misc.Unsafe;
 
 /**
  * A package-local class holding common representation and mechanics
@@ -123,22 +126,21 @@ abstract class Striped64 extends Number {
         volatile long value;
         Cell(long x) { value = x; }
         final boolean cas(long cmp, long val) {
-            return U.compareAndSwapLong(this, VALUE, cmp, val);
+            return VALUE.compareAndSet(this, cmp, val);
         }
         final void reset() {
-            U.putLongVolatile(this, VALUE, 0L);
+            VALUE.setVolatile(this, 0L);
         }
         final void reset(long identity) {
-            U.putLongVolatile(this, VALUE, identity);
+            VALUE.setVolatile(this, identity);
         }
 
-        // Unsafe mechanics
-        private static final jdk.internal.misc.Unsafe U = jdk.internal.misc.Unsafe.getUnsafe();
-        private static final long VALUE;
+        // VarHandle mechanics
+        private static final VarHandle VALUE;
         static {
             try {
-                VALUE = U.objectFieldOffset
-                    (Cell.class.getDeclaredField("value"));
+                MethodHandles.Lookup l = MethodHandles.lookup();
+                VALUE = l.findVarHandle(Cell.class, "value", long.class);
             } catch (ReflectiveOperationException e) {
                 throw new Error(e);
             }
@@ -174,14 +176,14 @@ abstract class Striped64 extends Number {
      * CASes the base field.
      */
     final boolean casBase(long cmp, long val) {
-        return U.compareAndSwapLong(this, BASE, cmp, val);
+        return BASE.compareAndSet(this, cmp, val);
     }
 
     /**
      * CASes the cellsBusy field from 0 to 1 to acquire lock.
      */
     final boolean casCellsBusy() {
-        return U.compareAndSwapInt(this, CELLSBUSY, 0, 1);
+        return CELLSBUSY.compareAndSet(this, 0, 1);
     }
 
     /**
@@ -371,18 +373,16 @@ abstract class Striped64 extends Number {
         }
     }
 
-    // Unsafe mechanics
-    private static final jdk.internal.misc.Unsafe U = jdk.internal.misc.Unsafe.getUnsafe();
-    private static final long BASE;
-    private static final long CELLSBUSY;
+    // Unsafe and VarHandle mechanics
+    private static final Unsafe U = Unsafe.getUnsafe();
+    private static final VarHandle BASE;
+    private static final VarHandle CELLSBUSY;
     private static final long PROBE;
     static {
         try {
-            BASE = U.objectFieldOffset
-                (Striped64.class.getDeclaredField("base"));
-            CELLSBUSY = U.objectFieldOffset
-                (Striped64.class.getDeclaredField("cellsBusy"));
-
+            MethodHandles.Lookup l = MethodHandles.lookup();
+            BASE = l.findVarHandle(Striped64.class, "base", long.class);
+            CELLSBUSY = l.findVarHandle(Striped64.class, "cellsBusy", int.class);
             PROBE = U.objectFieldOffset
                 (Thread.class.getDeclaredField("threadLocalRandomProbe"));
         } catch (ReflectiveOperationException e) {

jdk/src/java.base/share/classes/java/util/concurrent/atomic/package-info.java

@@ -35,26 +35,10 @@
 
 /**
  * A small toolkit of classes that support lock-free thread-safe
- * programming on single variables.  In essence, the classes in this
- * package extend the notion of {@code volatile} values, fields, and
- * array elements to those that also provide an atomic conditional update
- * operation of the form:
- *
- * <pre> {@code boolean compareAndSet(expectedValue, updateValue);}</pre>
- *
- * <p>This method (which varies in argument types across different
- * classes) atomically sets a variable to the {@code updateValue} if it
- * currently holds the {@code expectedValue}, reporting {@code true} on
- * success.  The classes in this package also contain methods to get and
- * unconditionally set values, as well as a weaker conditional atomic
- * update operation {@code weakCompareAndSet} described below.
- *
- * <p>The specifications of these methods enable implementations to
- * employ efficient machine-level atomic instructions that are available
- * on contemporary processors.  However on some platforms, support may
- * entail some form of internal locking.  Thus the methods are not
- * strictly guaranteed to be non-blocking --
- * a thread may block transiently before performing the operation.
+ * programming on single variables.  Instances of Atomic classes
+ * maintain values that are accessed and updated using methods
+ * otherwise available for fields using associated atomic {@link
+ * java.lang.invoke.VarHandle} operations.
  *
  * <p>Instances of classes
  * {@link java.util.concurrent.atomic.AtomicBoolean},
@@ -92,45 +76,26 @@
  *   return prev; // return next; for transformAndGet
  * }}</pre>
  *
- * <p>The memory effects for accesses and updates of atomics generally
- * follow the rules for volatiles, as stated in
- * <a href="https://docs.oracle.com/javase/specs/jls/se8/html/jls-17.html#jls-17.4">
- * Chapter 17 of
- * <cite>The Java&trade; Language Specification</cite></a>:
+ * <p>These classes are not general purpose replacements for {@code
+ * java.lang.Integer} and related classes.  They do <em>not</em>
+ * define methods such as {@code equals}, {@code hashCode} and {@code
+ * compareTo}.  Because atomic variables are expected to be mutated,
+ * they are poor choices for hash table keys.
  *
- * <ul>
- *
- *   <li>{@code get} has the memory effects of reading a
- * {@code volatile} variable.
- *
- *   <li>{@code set} has the memory effects of writing (assigning) a
- * {@code volatile} variable.
- *
- *   <li>{@code lazySet} has the memory effects of writing (assigning)
- *   a {@code volatile} variable except that it permits reorderings with
- *   subsequent (but not previous) memory actions that do not themselves
- *   impose reordering constraints with ordinary non-{@code volatile}
- *   writes.  Among other usage contexts, {@code lazySet} may apply when
- *   nulling out, for the sake of garbage collection, a reference that is
- *   never accessed again.
- *
- *   <li>{@code weakCompareAndSet} atomically reads and conditionally
- *   writes a variable but does <em>not</em>
- *   create any happens-before orderings, so provides no guarantees
- *   with respect to previous or subsequent reads and writes of any
- *   variables other than the target of the {@code weakCompareAndSet}.
- *
- *   <li>{@code compareAndSet}
- *   and all other read-and-update operations such as {@code getAndIncrement}
- *   have the memory effects of both reading and
- *   writing {@code volatile} variables.
- * </ul>
- *
- * <p>In addition to classes representing single values, this package
- * contains <em>Updater</em> classes that can be used to obtain
- * {@code compareAndSet} operations on any selected {@code volatile}
- * field of any selected class.
+ * <p>The
+ * {@link java.util.concurrent.atomic.AtomicIntegerArray},
+ * {@link java.util.concurrent.atomic.AtomicLongArray}, and
+ * {@link java.util.concurrent.atomic.AtomicReferenceArray} classes
+ * further extend atomic operation support to arrays of these types.
+ * These classes are also notable in providing {@code volatile} access
+ * semantics for their array elements.
  *
+ * <p>In addition to classes representing single values and arrays,
+ * this package contains <em>Updater</em> classes that can be used to
+ * obtain {@code compareAndSet} and related operations on any selected
+ * {@code volatile} field of any selected class. These classes
+ * predate the introduction of {@link
+ * java.lang.invoke.VarHandle}, and are of more limited use.
  * {@link java.util.concurrent.atomic.AtomicReferenceFieldUpdater},
  * {@link java.util.concurrent.atomic.AtomicIntegerFieldUpdater}, and
  * {@link java.util.concurrent.atomic.AtomicLongFieldUpdater} are
@@ -143,38 +108,6 @@
  * reflection-based setup, less convenient usage, and weaker
  * guarantees.
  *
- * <p>The
- * {@link java.util.concurrent.atomic.AtomicIntegerArray},
- * {@link java.util.concurrent.atomic.AtomicLongArray}, and
- * {@link java.util.concurrent.atomic.AtomicReferenceArray} classes
- * further extend atomic operation support to arrays of these types.
- * These classes are also notable in providing {@code volatile} access
- * semantics for their array elements, which is not supported for
- * ordinary arrays.
- *
- * <p id="weakCompareAndSet">The atomic classes also support method
- * {@code weakCompareAndSet}, which has limited applicability.  On some
- * platforms, the weak version may be more efficient than {@code
- * compareAndSet} in the normal case, but differs in that any given
- * invocation of the {@code weakCompareAndSet} method may return {@code
- * false} <em>spuriously</em> (that is, for no apparent reason).  A
- * {@code false} return means only that the operation may be retried if
- * desired, relying on the guarantee that repeated invocation when the
- * variable holds {@code expectedValue} and no other thread is also
- * attempting to set the variable will eventually succeed.  (Such
- * spurious failures may for example be due to memory contention effects
- * that are unrelated to whether the expected and current values are
- * equal.)  Additionally {@code weakCompareAndSet} does not provide
- * ordering guarantees that are usually needed for synchronization
- * control.  However, the method may be useful for updating counters and
- * statistics when such updates are unrelated to the other
- * happens-before orderings of a program.  When a thread sees an update
- * to an atomic variable caused by a {@code weakCompareAndSet}, it does
- * not necessarily see updates to any <em>other</em> variables that
- * occurred before the {@code weakCompareAndSet}.  This may be
- * acceptable when, for example, updating performance statistics, but
- * rarely otherwise.
- *
  * <p>The {@link java.util.concurrent.atomic.AtomicMarkableReference}
  * class associates a single boolean with a reference.  For example, this
  * bit might be used inside a data structure to mean that the object
@@ -185,29 +118,6 @@
  * used for example, to represent version numbers corresponding to
  * series of updates.
  *
- * <p>Atomic classes are designed primarily as building blocks for
- * implementing non-blocking data structures and related infrastructure
- * classes.  The {@code compareAndSet} method is not a general
- * replacement for locking.  It applies only when critical updates for an
- * object are confined to a <em>single</em> variable.
- *
- * <p>Atomic classes are not general purpose replacements for
- * {@code java.lang.Integer} and related classes.  They do <em>not</em>
- * define methods such as {@code equals}, {@code hashCode} and
- * {@code compareTo}.  (Because atomic variables are expected to be
- * mutated, they are poor choices for hash table keys.)  Additionally,
- * classes are provided only for those types that are commonly useful in
- * intended applications.  For example, there is no atomic class for
- * representing {@code byte}.  In those infrequent cases where you would
- * like to do so, you can use an {@code AtomicInteger} to hold
- * {@code byte} values, and cast appropriately.
- *
- * You can also hold floats using
- * {@link java.lang.Float#floatToRawIntBits} and
- * {@link java.lang.Float#intBitsToFloat} conversions, and doubles using
- * {@link java.lang.Double#doubleToRawLongBits} and
- * {@link java.lang.Double#longBitsToDouble} conversions.
- *
  * @since 1.5
  */
 package java.util.concurrent.atomic;

jdk/src/java.base/share/classes/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.java

@@ -35,6 +35,8 @@
 
 package java.util.concurrent.locks;
 
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.VarHandle;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Date;
@@ -113,7 +115,7 @@ public abstract class AbstractQueuedLongSynchronizer
     protected final void setState(long newState) {
         // Use putLongVolatile instead of ordinary volatile store when
         // using compareAndSwapLong, for sake of some 32bit systems.
-        U.putLongVolatile(this, STATE, newState);
+        STATE.setVolatile(this, newState);
     }
 
     /**
@@ -128,7 +130,7 @@ public abstract class AbstractQueuedLongSynchronizer
      *         value was not equal to the expected value.
      */
     protected final boolean compareAndSetState(long expect, long update) {
-        return U.compareAndSwapLong(this, STATE, expect, update);
+        return STATE.compareAndSet(this, expect, update);
     }
 
     // Queuing utilities
@@ -149,7 +151,7 @@ public abstract class AbstractQueuedLongSynchronizer
         for (;;) {
             Node oldTail = tail;
             if (oldTail != null) {
-                U.putObject(node, Node.PREV, oldTail);
+                node.setPrevRelaxed(oldTail);
                 if (compareAndSetTail(oldTail, node)) {
                     oldTail.next = node;
                     return oldTail;
@@ -172,7 +174,7 @@ public abstract class AbstractQueuedLongSynchronizer
         for (;;) {
             Node oldTail = tail;
             if (oldTail != null) {
-                U.putObject(node, Node.PREV, oldTail);
+                node.setPrevRelaxed(oldTail);
                 if (compareAndSetTail(oldTail, node)) {
                     oldTail.next = node;
                     return node;
@@ -1810,28 +1812,17 @@ public abstract class AbstractQueuedLongSynchronizer
         }
     }
 
-    /**
-     * Setup to support compareAndSet. We need to natively implement
-     * this here: For the sake of permitting future enhancements, we
-     * cannot explicitly subclass AtomicLong, which would be
-     * efficient and useful otherwise. So, as the lesser of evils, we
-     * natively implement using hotspot intrinsics API. And while we
-     * are at it, we do the same for other CASable fields (which could
-     * otherwise be done with atomic field updaters).
-     */
-    private static final jdk.internal.misc.Unsafe U = jdk.internal.misc.Unsafe.getUnsafe();
-    private static final long STATE;
-    private static final long HEAD;
-    private static final long TAIL;
+    // VarHandle mechanics
+    private static final VarHandle STATE;
+    private static final VarHandle HEAD;
+    private static final VarHandle TAIL;
 
     static {
         try {
-            STATE = U.objectFieldOffset
-                (AbstractQueuedLongSynchronizer.class.getDeclaredField("state"));
-            HEAD = U.objectFieldOffset
-                (AbstractQueuedLongSynchronizer.class.getDeclaredField("head"));
-            TAIL = U.objectFieldOffset
-                (AbstractQueuedLongSynchronizer.class.getDeclaredField("tail"));
+            MethodHandles.Lookup l = MethodHandles.lookup();
+            STATE = l.findVarHandle(AbstractQueuedLongSynchronizer.class, "state", long.class);
+            HEAD = l.findVarHandle(AbstractQueuedLongSynchronizer.class, "head", Node.class);
+            TAIL = l.findVarHandle(AbstractQueuedLongSynchronizer.class, "tail", Node.class);
         } catch (ReflectiveOperationException e) {
             throw new Error(e);
         }
@@ -1846,7 +1837,7 @@ public abstract class AbstractQueuedLongSynchronizer
      */
     private final void initializeSyncQueue() {
         Node h;
-        if (U.compareAndSwapObject(this, HEAD, null, (h = new Node())))
+        if (HEAD.compareAndSet(this, null, (h = new Node())))
             tail = h;
     }
 
@@ -1854,6 +1845,6 @@ public abstract class AbstractQueuedLongSynchronizer
      * CASes tail field.
      */
     private final boolean compareAndSetTail(Node expect, Node update) {
-        return U.compareAndSwapObject(this, TAIL, expect, update);
+        return TAIL.compareAndSet(this, expect, update);
     }
 }

jdk/src/java.base/share/classes/java/util/concurrent/locks/AbstractQueuedSynchronizer.java

@@ -35,11 +35,12 @@
 
 package java.util.concurrent.locks;
 
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.VarHandle;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Date;
 import java.util.concurrent.TimeUnit;
-import jdk.internal.vm.annotation.ReservedStackAccess;
 
 /**
  * Provides a framework for implementing blocking locks and related
@@ -506,40 +507,41 @@ public abstract class AbstractQueuedSynchronizer
         /** Constructor used by addWaiter. */
         Node(Node nextWaiter) {
             this.nextWaiter = nextWaiter;
-            U.putObject(this, THREAD, Thread.currentThread());
+            THREAD.set(this, Thread.currentThread());
         }
 
         /** Constructor used by addConditionWaiter. */
         Node(int waitStatus) {
-            U.putInt(this, WAITSTATUS, waitStatus);
-            U.putObject(this, THREAD, Thread.currentThread());
+            WAITSTATUS.set(this, waitStatus);
+            THREAD.set(this, Thread.currentThread());
         }
 
         /** CASes waitStatus field. */
         final boolean compareAndSetWaitStatus(int expect, int update) {
-            return U.compareAndSwapInt(this, WAITSTATUS, expect, update);
+            return WAITSTATUS.compareAndSet(this, expect, update);
         }
 
         /** CASes next field. */
         final boolean compareAndSetNext(Node expect, Node update) {
-            return U.compareAndSwapObject(this, NEXT, expect, update);
+            return NEXT.compareAndSet(this, expect, update);
         }
 
-        private static final jdk.internal.misc.Unsafe U = jdk.internal.misc.Unsafe.getUnsafe();
-        private static final long NEXT;
-        static final long PREV;
-        private static final long THREAD;
-        private static final long WAITSTATUS;
+        final void setPrevRelaxed(Node p) {
+            PREV.set(this, p);
+        }
+
+        // VarHandle mechanics
+        private static final VarHandle NEXT;
+        private static final VarHandle PREV;
+        private static final VarHandle THREAD;
+        private static final VarHandle WAITSTATUS;
         static {
             try {
-                NEXT = U.objectFieldOffset
-                    (Node.class.getDeclaredField("next"));
-                PREV = U.objectFieldOffset
-                    (Node.class.getDeclaredField("prev"));
-                THREAD = U.objectFieldOffset
-                    (Node.class.getDeclaredField("thread"));
-                WAITSTATUS = U.objectFieldOffset
-                    (Node.class.getDeclaredField("waitStatus"));
+                MethodHandles.Lookup l = MethodHandles.lookup();
+                NEXT = l.findVarHandle(Node.class, "next", Node.class);
+                PREV = l.findVarHandle(Node.class, "prev", Node.class);
+                THREAD = l.findVarHandle(Node.class, "thread", Thread.class);
+                WAITSTATUS = l.findVarHandle(Node.class, "waitStatus", int.class);
             } catch (ReflectiveOperationException e) {
                 throw new Error(e);
             }
@@ -595,7 +597,7 @@ public abstract class AbstractQueuedSynchronizer
      *         value was not equal to the expected value.
      */
     protected final boolean compareAndSetState(int expect, int update) {
-        return U.compareAndSwapInt(this, STATE, expect, update);
+        return STATE.compareAndSet(this, expect, update);
     }
 
     // Queuing utilities
@@ -616,7 +618,7 @@ public abstract class AbstractQueuedSynchronizer
         for (;;) {
             Node oldTail = tail;
             if (oldTail != null) {
-                U.putObject(node, Node.PREV, oldTail);
+                node.setPrevRelaxed(oldTail);
                 if (compareAndSetTail(oldTail, node)) {
                     oldTail.next = node;
                     return oldTail;
@@ -639,7 +641,7 @@ public abstract class AbstractQueuedSynchronizer
         for (;;) {
             Node oldTail = tail;
             if (oldTail != null) {
-                U.putObject(node, Node.PREV, oldTail);
+                node.setPrevRelaxed(oldTail);
                 if (compareAndSetTail(oldTail, node)) {
                     oldTail.next = node;
                     return node;
@@ -887,7 +889,6 @@ public abstract class AbstractQueuedSynchronizer
      * @param arg the acquire argument
      * @return {@code true} if interrupted while waiting
      */
-    @ReservedStackAccess
     final boolean acquireQueued(final Node node, int arg) {
         try {
             boolean interrupted = false;
@@ -1220,7 +1221,6 @@ public abstract class AbstractQueuedSynchronizer
      *        {@link #tryAcquire} but is otherwise uninterpreted and
      *        can represent anything you like.
      */
-    @ReservedStackAccess
     public final void acquire(int arg) {
         if (!tryAcquire(arg) &&
             acquireQueued(addWaiter(Node.EXCLUSIVE), arg))
@@ -1284,7 +1284,6 @@ public abstract class AbstractQueuedSynchronizer
      *        can represent anything you like.
      * @return the value returned from {@link #tryRelease}
      */
-    @ReservedStackAccess
     public final boolean release(int arg) {
         if (tryRelease(arg)) {
             Node h = head;
@@ -1365,7 +1364,6 @@ public abstract class AbstractQueuedSynchronizer
      *        and can represent anything you like.
      * @return the value returned from {@link #tryReleaseShared}
      */
-    @ReservedStackAccess
     public final boolean releaseShared(int arg) {
         if (tryReleaseShared(arg)) {
             doReleaseShared();
@@ -2279,28 +2277,17 @@ public abstract class AbstractQueuedSynchronizer
         }
     }
 
-    /**
-     * Setup to support compareAndSet. We need to natively implement
-     * this here: For the sake of permitting future enhancements, we
-     * cannot explicitly subclass AtomicInteger, which would be
-     * efficient and useful otherwise. So, as the lesser of evils, we
-     * natively implement using hotspot intrinsics API. And while we
-     * are at it, we do the same for other CASable fields (which could
-     * otherwise be done with atomic field updaters).
-     */
-    private static final jdk.internal.misc.Unsafe U = jdk.internal.misc.Unsafe.getUnsafe();
-    private static final long STATE;
-    private static final long HEAD;
-    private static final long TAIL;
+    // VarHandle mechanics
+    private static final VarHandle STATE;
+    private static final VarHandle HEAD;
+    private static final VarHandle TAIL;
 
     static {
         try {
-            STATE = U.objectFieldOffset
-                (AbstractQueuedSynchronizer.class.getDeclaredField("state"));
-            HEAD = U.objectFieldOffset
-                (AbstractQueuedSynchronizer.class.getDeclaredField("head"));
-            TAIL = U.objectFieldOffset
-                (AbstractQueuedSynchronizer.class.getDeclaredField("tail"));
+            MethodHandles.Lookup l = MethodHandles.lookup();
+            STATE = l.findVarHandle(AbstractQueuedSynchronizer.class, "state", int.class);
+            HEAD = l.findVarHandle(AbstractQueuedSynchronizer.class, "head", Node.class);
+            TAIL = l.findVarHandle(AbstractQueuedSynchronizer.class, "tail", Node.class);
         } catch (ReflectiveOperationException e) {
             throw new Error(e);
         }
@@ -2315,7 +2302,7 @@ public abstract class AbstractQueuedSynchronizer
      */
     private final void initializeSyncQueue() {
         Node h;
-        if (U.compareAndSwapObject(this, HEAD, null, (h = new Node())))
+        if (HEAD.compareAndSet(this, null, (h = new Node())))
             tail = h;
     }
 
@@ -2323,6 +2310,6 @@ public abstract class AbstractQueuedSynchronizer
      * CASes tail field.
      */
     private final boolean compareAndSetTail(Node expect, Node update) {
-        return U.compareAndSwapObject(this, TAIL, expect, update);
+        return TAIL.compareAndSet(this, expect, update);
     }
 }

jdk/src/java.base/share/classes/java/util/concurrent/locks/Condition.java

@@ -396,7 +396,6 @@ public interface Condition {
      * re-acquire the lock associated with this condition. When the
      * thread returns it is <em>guaranteed</em> to hold this lock.
      *
-     *
      * <p>If the current thread:
      * <ul>
      * <li>has its interrupted status set on entry to this method; or
@@ -408,7 +407,6 @@ public interface Condition {
      * case, whether or not the test for interruption occurs before the lock
      * is released.
      *
-     *
      * <p>The return value indicates whether the deadline has elapsed,
      * which can be used as follows:
      * <pre> {@code

jdk/src/java.base/share/classes/java/util/concurrent/locks/LockSupport.java

@@ -35,6 +35,8 @@
 
 package java.util.concurrent.locks;
 
+import jdk.internal.misc.Unsafe;
+
 /**
  * Basic thread blocking primitives for creating locks and other
  * synchronization classes.
@@ -405,16 +407,30 @@ public class LockSupport {
         return r;
     }
 
+    /**
+     * Returns the thread id for the given thread.  We must access
+     * this directly rather than via method Thread.getId() because
+     * getId() is not final, and has been known to be overridden in
+     * ways that do not preserve unique mappings.
+     */
+    static final long getThreadId(Thread thread) {
+        return U.getLongVolatile(thread, TID);
+    }
+
     // Hotspot implementation via intrinsics API
-    private static final jdk.internal.misc.Unsafe U = jdk.internal.misc.Unsafe.getUnsafe();
+    private static final Unsafe U = Unsafe.getUnsafe();
     private static final long PARKBLOCKER;
     private static final long SECONDARY;
+    private static final long TID;
     static {
         try {
             PARKBLOCKER = U.objectFieldOffset
                 (Thread.class.getDeclaredField("parkBlocker"));
             SECONDARY = U.objectFieldOffset
                 (Thread.class.getDeclaredField("threadLocalRandomSecondarySeed"));
+            TID = U.objectFieldOffset
+                (Thread.class.getDeclaredField("tid"));
+
         } catch (ReflectiveOperationException e) {
             throw new Error(e);
         }

jdk/src/java.base/share/classes/java/util/concurrent/locks/ReadWriteLock.java

@@ -79,7 +79,6 @@ package java.util.concurrent.locks;
  * and measurement will establish whether the use of a read-write lock is
  * suitable for your application.
  *
- *
  * <p>Although the basic operation of a read-write lock is straight-forward,
  * there are many policy decisions that an implementation must make, which
  * may affect the effectiveness of the read-write lock in a given application.

jdk/src/java.base/share/classes/java/util/concurrent/locks/ReentrantLock.java

@@ -118,12 +118,6 @@ public class ReentrantLock implements Lock, java.io.Serializable {
     abstract static class Sync extends AbstractQueuedSynchronizer {
         private static final long serialVersionUID = -5179523762034025860L;
 
-        /**
-         * Performs {@link Lock#lock}. The main reason for subclassing
-         * is to allow fast path for nonfair version.
-         */
-        abstract void lock();
-
         /**
          * Performs non-fair tryLock.  tryAcquire is implemented in
          * subclasses, but both need nonfair try for trylock method.
@@ -201,19 +195,6 @@ public class ReentrantLock implements Lock, java.io.Serializable {
      */
     static final class NonfairSync extends Sync {
         private static final long serialVersionUID = 7316153563782823691L;
-
-        /**
-         * Performs lock.  Try immediate barge, backing up to normal
-         * acquire on failure.
-         */
-        @ReservedStackAccess
-        final void lock() {
-            if (compareAndSetState(0, 1))
-                setExclusiveOwnerThread(Thread.currentThread());
-            else
-                acquire(1);
-        }
-
         protected final boolean tryAcquire(int acquires) {
             return nonfairTryAcquire(acquires);
         }
@@ -224,11 +205,6 @@ public class ReentrantLock implements Lock, java.io.Serializable {
      */
     static final class FairSync extends Sync {
         private static final long serialVersionUID = -3000897897090466540L;
-
-        final void lock() {
-            acquire(1);
-        }
-
         /**
          * Fair version of tryAcquire.  Don't grant access unless
          * recursive call or no waiters or is first.
@@ -288,7 +264,7 @@ public class ReentrantLock implements Lock, java.io.Serializable {
      * at which time the lock hold count is set to one.
      */
     public void lock() {
-        sync.lock();
+        sync.acquire(1);
     }
 
     /**

jdk/src/java.base/share/classes/java/util/concurrent/locks/ReentrantReadWriteLock.java

@@ -37,6 +37,7 @@ package java.util.concurrent.locks;
 
 import java.util.Collection;
 import java.util.concurrent.TimeUnit;
+import jdk.internal.vm.annotation.ReservedStackAccess;
 
 /**
  * An implementation of {@link ReadWriteLock} supporting similar
@@ -278,7 +279,7 @@ public class ReentrantReadWriteLock
         static final class HoldCounter {
             int count;          // initially 0
             // Use id, not reference, to avoid garbage retention
-            final long tid = getThreadId(Thread.currentThread());
+            final long tid = LockSupport.getThreadId(Thread.currentThread());
         }
 
         /**
@@ -367,7 +368,7 @@ public class ReentrantReadWriteLock
          * both read and write holds that are all released during a
          * condition wait and re-established in tryAcquire.
          */
-
+        @ReservedStackAccess
         protected final boolean tryRelease(int releases) {
             if (!isHeldExclusively())
                 throw new IllegalMonitorStateException();
@@ -379,6 +380,7 @@ public class ReentrantReadWriteLock
             return free;
         }
 
+        @ReservedStackAccess
         protected final boolean tryAcquire(int acquires) {
             /*
              * Walkthrough:
@@ -411,6 +413,7 @@ public class ReentrantReadWriteLock
             return true;
         }
 
+        @ReservedStackAccess
         protected final boolean tryReleaseShared(int unused) {
             Thread current = Thread.currentThread();
             if (firstReader == current) {
@@ -421,7 +424,8 @@ public class ReentrantReadWriteLock
                     firstReaderHoldCount--;
             } else {
                 HoldCounter rh = cachedHoldCounter;
-                if (rh == null || rh.tid != getThreadId(current))
+                if (rh == null ||
+                    rh.tid != LockSupport.getThreadId(current))
                     rh = readHolds.get();
                 int count = rh.count;
                 if (count <= 1) {
@@ -447,6 +451,7 @@ public class ReentrantReadWriteLock
                 "attempt to unlock read lock, not locked by current thread");
         }
 
+        @ReservedStackAccess
         protected final int tryAcquireShared(int unused) {
             /*
              * Walkthrough:
@@ -479,7 +484,8 @@ public class ReentrantReadWriteLock
                     firstReaderHoldCount++;
                 } else {
                     HoldCounter rh = cachedHoldCounter;
-                    if (rh == null || rh.tid != getThreadId(current))
+                    if (rh == null ||
+                        rh.tid != LockSupport.getThreadId(current))
                         cachedHoldCounter = rh = readHolds.get();
                     else if (rh.count == 0)
                         readHolds.set(rh);
@@ -516,7 +522,8 @@ public class ReentrantReadWriteLock
                     } else {
                         if (rh == null) {
                             rh = cachedHoldCounter;
-                            if (rh == null || rh.tid != getThreadId(current)) {
+                            if (rh == null ||
+                                rh.tid != LockSupport.getThreadId(current)) {
                                 rh = readHolds.get();
                                 if (rh.count == 0)
                                     readHolds.remove();
@@ -537,7 +544,8 @@ public class ReentrantReadWriteLock
                     } else {
                         if (rh == null)
                             rh = cachedHoldCounter;
-                        if (rh == null || rh.tid != getThreadId(current))
+                        if (rh == null ||
+                            rh.tid != LockSupport.getThreadId(current))
                             rh = readHolds.get();
                         else if (rh.count == 0)
                             readHolds.set(rh);
@@ -554,6 +562,7 @@ public class ReentrantReadWriteLock
          * This is identical in effect to tryAcquire except for lack
          * of calls to writerShouldBlock.
          */
+        @ReservedStackAccess
         final boolean tryWriteLock() {
             Thread current = Thread.currentThread();
             int c = getState();
@@ -575,6 +584,7 @@ public class ReentrantReadWriteLock
          * This is identical in effect to tryAcquireShared except for
          * lack of calls to readerShouldBlock.
          */
+        @ReservedStackAccess
         final boolean tryReadLock() {
             Thread current = Thread.currentThread();
             for (;;) {
@@ -593,7 +603,8 @@ public class ReentrantReadWriteLock
                         firstReaderHoldCount++;
                     } else {
                         HoldCounter rh = cachedHoldCounter;
-                        if (rh == null || rh.tid != getThreadId(current))
+                        if (rh == null ||
+                            rh.tid != LockSupport.getThreadId(current))
                             cachedHoldCounter = rh = readHolds.get();
                         else if (rh.count == 0)
                             readHolds.set(rh);
@@ -644,7 +655,7 @@ public class ReentrantReadWriteLock
                 return firstReaderHoldCount;
 
             HoldCounter rh = cachedHoldCounter;
-            if (rh != null && rh.tid == getThreadId(current))
+            if (rh != null && rh.tid == LockSupport.getThreadId(current))
                 return rh.count;
 
             int count = readHolds.get().count;
@@ -1490,26 +1501,4 @@ public class ReentrantReadWriteLock
             "[Write locks = " + w + ", Read locks = " + r + "]";
     }
 
-    /**
-     * Returns the thread id for the given thread.  We must access
-     * this directly rather than via method Thread.getId() because
-     * getId() is not final, and has been known to be overridden in
-     * ways that do not preserve unique mappings.
-     */
-    static final long getThreadId(Thread thread) {
-        return U.getLongVolatile(thread, TID);
-    }
-
-    // Unsafe mechanics
-    private static final jdk.internal.misc.Unsafe U = jdk.internal.misc.Unsafe.getUnsafe();
-    private static final long TID;
-    static {
-        try {
-            TID = U.objectFieldOffset
-                (Thread.class.getDeclaredField("tid"));
-        } catch (ReflectiveOperationException e) {
-            throw new Error(e);
-        }
-    }
-
 }

jdk/src/java.base/share/classes/java/util/concurrent/locks/StampedLock.java

@@ -35,7 +35,10 @@
 
 package java.util.concurrent.locks;
 
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.VarHandle;
 import java.util.concurrent.TimeUnit;
+import jdk.internal.vm.annotation.ReservedStackAccess;
 
 /**
  * A capability-based lock with three modes for controlling read/write
@@ -108,6 +111,10 @@ import java.util.concurrent.TimeUnit;
  * into initial unlocked state, so they are not useful for remote
  * locking.
  *
+ * <p>Like {@link java.util.concurrent.Semaphore Semaphore}, but unlike most
+ * {@link Lock} implementations, StampedLocks have no notion of ownership.
+ * Locks acquired in one thread can be released or converted in another.
+ *
  * <p>The scheduling policy of StampedLock does not consistently
  * prefer readers over writers or vice versa.  All "try" methods are
  * best-effort and do not necessarily conform to any scheduling or
@@ -126,7 +133,7 @@ import java.util.concurrent.TimeUnit;
  * in a class that maintains simple two-dimensional points. The sample
  * code illustrates some try/catch conventions even though they are
  * not strictly needed here because no exceptions can occur in their
- * bodies.<br>
+ * bodies.
  *
  * <pre> {@code
  * class Point {
@@ -234,9 +241,7 @@ public class StampedLock implements java.io.Serializable {
      * used in the acquire methods to reduce (increasingly expensive)
      * context switching while also avoiding sustained memory
      * thrashing among many threads.  We limit spins to the head of
-     * queue. A thread spin-waits up to SPINS times (where each
-     * iteration decreases spin count with 50% probability) before
-     * blocking. If, upon wakening it fails to obtain lock, and is
+     * queue. If, upon wakening, a thread fails to obtain lock, and is
      * still (or becomes) the first waiting thread (which indicates
      * that some other thread barged and obtained lock), it escalates
      * spins (up to MAX_HEAD_SPINS) to reduce the likelihood of
@@ -252,7 +257,7 @@ public class StampedLock implements java.io.Serializable {
      * to normal volatile reads (of "state").  To force orderings of
      * reads before a validation and the validation itself in those
      * cases where this is not already forced, we use
-     * Unsafe.loadFence.
+     * VarHandle.acquireFence.
      *
      * The memory layout keeps lock state and queue pointers together
      * (normally on the same cache line). This usually works well for
@@ -290,7 +295,20 @@ public class StampedLock implements java.io.Serializable {
     private static final long ABITS = RBITS | WBIT;
     private static final long SBITS = ~RBITS; // note overlap with ABITS
 
-    // Initial value for lock state; avoid failure value zero
+    /*
+     * 3 stamp modes can be distinguished by examining (m = stamp & ABITS):
+     * write mode: m == WBIT
+     * optimistic read mode: m == 0L (even when read lock is held)
+     * read mode: m > 0L && m <= RFULL (the stamp is a copy of state, but the
+     * read hold count in the stamp is unused other than to determine mode)
+     *
+     * This differs slightly from the encoding of state:
+     * (state & ABITS) == 0L indicates the lock is currently unlocked.
+     * (state & ABITS) == RBITS is a special transient value
+     * indicating spin-locked to manipulate reader bits overflow.
+     */
+
+    /** Initial value for lock state; avoids failure value zero. */
     private static final long ORIGIN = WBIT << 1;
 
     // Special value from cancelled acquire methods so caller can throw IE
@@ -341,25 +359,27 @@ public class StampedLock implements java.io.Serializable {
      * Exclusively acquires the lock, blocking if necessary
      * until available.
      *
-     * @return a stamp that can be used to unlock or convert mode
+     * @return a write stamp that can be used to unlock or convert mode
      */
+    @ReservedStackAccess
     public long writeLock() {
         long s, next;  // bypass acquireWrite in fully unlocked case only
         return ((((s = state) & ABITS) == 0L &&
-                 U.compareAndSwapLong(this, STATE, s, next = s + WBIT)) ?
+                 STATE.compareAndSet(this, s, next = s + WBIT)) ?
                 next : acquireWrite(false, 0L));
     }
 
     /**
      * Exclusively acquires the lock if it is immediately available.
      *
-     * @return a stamp that can be used to unlock or convert mode,
+     * @return a write stamp that can be used to unlock or convert mode,
      * or zero if the lock is not available
      */
+    @ReservedStackAccess
     public long tryWriteLock() {
         long s, next;
         return ((((s = state) & ABITS) == 0L &&
-                 U.compareAndSwapLong(this, STATE, s, next = s + WBIT)) ?
+                 STATE.compareAndSet(this, s, next = s + WBIT)) ?
                 next : 0L);
     }
 
@@ -371,7 +391,7 @@ public class StampedLock implements java.io.Serializable {
      *
      * @param time the maximum time to wait for the lock
      * @param unit the time unit of the {@code time} argument
-     * @return a stamp that can be used to unlock or convert mode,
+     * @return a write stamp that can be used to unlock or convert mode,
      * or zero if the lock is not available
      * @throws InterruptedException if the current thread is interrupted
      * before acquiring the lock
@@ -399,10 +419,11 @@ public class StampedLock implements java.io.Serializable {
      * Behavior under interruption matches that specified
      * for method {@link Lock#lockInterruptibly()}.
      *
-     * @return a stamp that can be used to unlock or convert mode
+     * @return a write stamp that can be used to unlock or convert mode
      * @throws InterruptedException if the current thread is interrupted
      * before acquiring the lock
      */
+    @ReservedStackAccess
     public long writeLockInterruptibly() throws InterruptedException {
         long next;
         if (!Thread.interrupted() &&
@@ -415,33 +436,34 @@ public class StampedLock implements java.io.Serializable {
      * Non-exclusively acquires the lock, blocking if necessary
      * until available.
      *
-     * @return a stamp that can be used to unlock or convert mode
+     * @return a read stamp that can be used to unlock or convert mode
      */
+    @ReservedStackAccess
     public long readLock() {
         long s = state, next;  // bypass acquireRead on common uncontended case
         return ((whead == wtail && (s & ABITS) < RFULL &&
-                 U.compareAndSwapLong(this, STATE, s, next = s + RUNIT)) ?
+                 STATE.compareAndSet(this, s, next = s + RUNIT)) ?
                 next : acquireRead(false, 0L));
     }
 
     /**
      * Non-exclusively acquires the lock if it is immediately available.
      *
-     * @return a stamp that can be used to unlock or convert mode,
+     * @return a read stamp that can be used to unlock or convert mode,
      * or zero if the lock is not available
      */
+    @ReservedStackAccess
     public long tryReadLock() {
-        for (;;) {
-            long s, m, next;
-            if ((m = (s = state) & ABITS) == WBIT)
-                return 0L;
-            else if (m < RFULL) {
-                if (U.compareAndSwapLong(this, STATE, s, next = s + RUNIT))
+        long s, m, next;
+        while ((m = (s = state) & ABITS) != WBIT) {
+            if (m < RFULL) {
+                if (STATE.compareAndSet(this, s, next = s + RUNIT))
                     return next;
             }
             else if ((next = tryIncReaderOverflow(s)) != 0L)
                 return next;
         }
+        return 0L;
     }
 
     /**
@@ -452,11 +474,12 @@ public class StampedLock implements java.io.Serializable {
      *
      * @param time the maximum time to wait for the lock
      * @param unit the time unit of the {@code time} argument
-     * @return a stamp that can be used to unlock or convert mode,
+     * @return a read stamp that can be used to unlock or convert mode,
      * or zero if the lock is not available
      * @throws InterruptedException if the current thread is interrupted
      * before acquiring the lock
      */
+    @ReservedStackAccess
     public long tryReadLock(long time, TimeUnit unit)
         throws InterruptedException {
         long s, m, next, deadline;
@@ -464,7 +487,7 @@ public class StampedLock implements java.io.Serializable {
         if (!Thread.interrupted()) {
             if ((m = (s = state) & ABITS) != WBIT) {
                 if (m < RFULL) {
-                    if (U.compareAndSwapLong(this, STATE, s, next = s + RUNIT))
+                    if (STATE.compareAndSet(this, s, next = s + RUNIT))
                         return next;
                 }
                 else if ((next = tryIncReaderOverflow(s)) != 0L)
@@ -486,10 +509,11 @@ public class StampedLock implements java.io.Serializable {
      * Behavior under interruption matches that specified
      * for method {@link Lock#lockInterruptibly()}.
      *
-     * @return a stamp that can be used to unlock or convert mode
+     * @return a read stamp that can be used to unlock or convert mode
      * @throws InterruptedException if the current thread is interrupted
      * before acquiring the lock
      */
+    @ReservedStackAccess
     public long readLockInterruptibly() throws InterruptedException {
         long next;
         if (!Thread.interrupted() &&
@@ -502,7 +526,7 @@ public class StampedLock implements java.io.Serializable {
      * Returns a stamp that can later be validated, or zero
      * if exclusively locked.
      *
-     * @return a stamp, or zero if exclusively locked
+     * @return a valid optimistic read stamp, or zero if exclusively locked
      */
     public long tryOptimisticRead() {
         long s;
@@ -522,10 +546,28 @@ public class StampedLock implements java.io.Serializable {
      * since issuance of the given stamp; else false
      */
     public boolean validate(long stamp) {
-        U.loadFence();
+        VarHandle.acquireFence();
         return (stamp & SBITS) == (state & SBITS);
     }
 
+    /**
+     * Returns an unlocked state, incrementing the version and
+     * avoiding special failure value 0L.
+     *
+     * @param s a write-locked state (or stamp)
+     */
+    private static long unlockWriteState(long s) {
+        return ((s += WBIT) == 0L) ? ORIGIN : s;
+    }
+
+    private long unlockWriteInternal(long s) {
+        long next; WNode h;
+        STATE.setVolatile(this, next = unlockWriteState(s));
+        if ((h = whead) != null && h.status != 0)
+            release(h);
+        return next;
+    }
+
     /**
      * If the lock state matches the given stamp, releases the
      * exclusive lock.
@@ -534,13 +576,11 @@ public class StampedLock implements java.io.Serializable {
      * @throws IllegalMonitorStateException if the stamp does
      * not match the current state of this lock
      */
+    @ReservedStackAccess
     public void unlockWrite(long stamp) {
-        WNode h;
         if (state != stamp || (stamp & WBIT) == 0L)
             throw new IllegalMonitorStateException();
-        U.putLongVolatile(this, STATE, (stamp += WBIT) == 0L ? ORIGIN : stamp);
-        if ((h = whead) != null && h.status != 0)
-            release(h);
+        unlockWriteInternal(stamp);
     }
 
     /**
@@ -551,22 +591,23 @@ public class StampedLock implements java.io.Serializable {
      * @throws IllegalMonitorStateException if the stamp does
      * not match the current state of this lock
      */
+    @ReservedStackAccess
     public void unlockRead(long stamp) {
         long s, m; WNode h;
-        for (;;) {
-            if (((s = state) & SBITS) != (stamp & SBITS) ||
-                (stamp & ABITS) == 0L || (m = s & ABITS) == 0L || m == WBIT)
-                throw new IllegalMonitorStateException();
+        while (((s = state) & SBITS) == (stamp & SBITS)
+               && (stamp & RBITS) > 0L
+               && ((m = s & RBITS) > 0L)) {
             if (m < RFULL) {
-                if (U.compareAndSwapLong(this, STATE, s, s - RUNIT)) {
+                if (STATE.compareAndSet(this, s, s - RUNIT)) {
                     if (m == RUNIT && (h = whead) != null && h.status != 0)
                         release(h);
-                    break;
+                    return;
                 }
             }
             else if (tryDecReaderOverflow(s) != 0L)
-                break;
+                return;
         }
+        throw new IllegalMonitorStateException();
     }
 
     /**
@@ -577,32 +618,12 @@ public class StampedLock implements java.io.Serializable {
      * @throws IllegalMonitorStateException if the stamp does
      * not match the current state of this lock
      */
+    @ReservedStackAccess
     public void unlock(long stamp) {
-        long a = stamp & ABITS, m, s; WNode h;
-        while (((s = state) & SBITS) == (stamp & SBITS)) {
-            if ((m = s & ABITS) == 0L)
-                break;
-            else if (m == WBIT) {
-                if (a != m)
-                    break;
-                U.putLongVolatile(this, STATE, (s += WBIT) == 0L ? ORIGIN : s);
-                if ((h = whead) != null && h.status != 0)
-                    release(h);
-                return;
-            }
-            else if (a == 0L || a >= WBIT)
-                break;
-            else if (m < RFULL) {
-                if (U.compareAndSwapLong(this, STATE, s, s - RUNIT)) {
-                    if (m == RUNIT && (h = whead) != null && h.status != 0)
-                        release(h);
-                    return;
-                }
-            }
-            else if (tryDecReaderOverflow(s) != 0L)
-                return;
-        }
-        throw new IllegalMonitorStateException();
+        if ((stamp & WBIT) != 0)
+            unlockWrite(stamp);
+        else
+            unlockRead(stamp);
     }
 
     /**
@@ -623,7 +644,7 @@ public class StampedLock implements java.io.Serializable {
             if ((m = s & ABITS) == 0L) {
                 if (a != 0L)
                     break;
-                if (U.compareAndSwapLong(this, STATE, s, next = s + WBIT))
+                if (STATE.compareAndSet(this, s, next = s + WBIT))
                     return next;
             }
             else if (m == WBIT) {
@@ -632,8 +653,7 @@ public class StampedLock implements java.io.Serializable {
                 return stamp;
             }
             else if (m == RUNIT && a != 0L) {
-                if (U.compareAndSwapLong(this, STATE, s,
-                                         next = s - RUNIT + WBIT))
+                if (STATE.compareAndSet(this, s, next = s - RUNIT + WBIT))
                     return next;
             }
             else
@@ -654,30 +674,32 @@ public class StampedLock implements java.io.Serializable {
      * @return a valid read stamp, or zero on failure
      */
     public long tryConvertToReadLock(long stamp) {
-        long a = stamp & ABITS, m, s, next; WNode h;
+        long a, s, next; WNode h;
         while (((s = state) & SBITS) == (stamp & SBITS)) {
-            if ((m = s & ABITS) == 0L) {
-                if (a != 0L)
+            if ((a = stamp & ABITS) >= WBIT) {
+                // write stamp
+                if (s != stamp)
                     break;
-                else if (m < RFULL) {
-                    if (U.compareAndSwapLong(this, STATE, s, next = s + RUNIT))
+                STATE.setVolatile(this, next = unlockWriteState(s) + RUNIT);
+                if ((h = whead) != null && h.status != 0)
+                    release(h);
+                return next;
+            }
+            else if (a == 0L) {
+                // optimistic read stamp
+                if ((s & ABITS) < RFULL) {
+                    if (STATE.compareAndSet(this, s, next = s + RUNIT))
                         return next;
                 }
                 else if ((next = tryIncReaderOverflow(s)) != 0L)
                     return next;
             }
-            else if (m == WBIT) {
-                if (a != m)
+            else {
+                // already a read stamp
+                if ((s & ABITS) == 0L)
                     break;
-                U.putLongVolatile(this, STATE, next = s + (WBIT + RUNIT));
-                if ((h = whead) != null && h.status != 0)
-                    release(h);
-                return next;
-            }
-            else if (a != 0L && a < WBIT)
                 return stamp;
-            else
-                break;
+            }
         }
         return 0L;
     }
@@ -693,29 +715,22 @@ public class StampedLock implements java.io.Serializable {
      * @return a valid optimistic read stamp, or zero on failure
      */
     public long tryConvertToOptimisticRead(long stamp) {
-        long a = stamp & ABITS, m, s, next; WNode h;
-        U.loadFence();
-        for (;;) {
-            if (((s = state) & SBITS) != (stamp & SBITS))
-                break;
-            if ((m = s & ABITS) == 0L) {
-                if (a != 0L)
+        long a, m, s, next; WNode h;
+        VarHandle.acquireFence();
+        while (((s = state) & SBITS) == (stamp & SBITS)) {
+            if ((a = stamp & ABITS) >= WBIT) {
+                // write stamp
+                if (s != stamp)
                     break;
-                return s;
+                return unlockWriteInternal(s);
             }
-            else if (m == WBIT) {
-                if (a != m)
-                    break;
-                U.putLongVolatile(this, STATE,
-                                  next = (s += WBIT) == 0L ? ORIGIN : s);
-                if ((h = whead) != null && h.status != 0)
-                    release(h);
-                return next;
-            }
-            else if (a == 0L || a >= WBIT)
+            else if (a == 0L)
+                // already an optimistic read stamp
+                return stamp;
+            else if ((m = s & ABITS) == 0L) // invalid read stamp
                 break;
             else if (m < RFULL) {
-                if (U.compareAndSwapLong(this, STATE, s, next = s - RUNIT)) {
+                if (STATE.compareAndSet(this, s, next = s - RUNIT)) {
                     if (m == RUNIT && (h = whead) != null && h.status != 0)
                         release(h);
                     return next & SBITS;
@@ -734,12 +749,11 @@ public class StampedLock implements java.io.Serializable {
      *
      * @return {@code true} if the lock was held, else false
      */
+    @ReservedStackAccess
     public boolean tryUnlockWrite() {
-        long s; WNode h;
+        long s;
         if (((s = state) & WBIT) != 0L) {
-            U.putLongVolatile(this, STATE, (s += WBIT) == 0L ? ORIGIN : s);
-            if ((h = whead) != null && h.status != 0)
-                release(h);
+            unlockWriteInternal(s);
             return true;
         }
         return false;
@@ -752,11 +766,12 @@ public class StampedLock implements java.io.Serializable {
      *
      * @return {@code true} if the read lock was held, else false
      */
+    @ReservedStackAccess
     public boolean tryUnlockRead() {
         long s, m; WNode h;
         while ((m = (s = state) & ABITS) != 0L && m < WBIT) {
             if (m < RFULL) {
-                if (U.compareAndSwapLong(this, STATE, s, s - RUNIT)) {
+                if (STATE.compareAndSet(this, s, s - RUNIT)) {
                     if (m == RUNIT && (h = whead) != null && h.status != 0)
                         release(h);
                     return true;
@@ -832,32 +847,30 @@ public class StampedLock implements java.io.Serializable {
      * Returns a plain {@link Lock} view of this StampedLock in which
      * the {@link Lock#lock} method is mapped to {@link #readLock},
      * and similarly for other methods. The returned Lock does not
-     * support a {@link Condition}; method {@link
-     * Lock#newCondition()} throws {@code
-     * UnsupportedOperationException}.
+     * support a {@link Condition}; method {@link Lock#newCondition()}
+     * throws {@code UnsupportedOperationException}.
      *
      * @return the lock
      */
     public Lock asReadLock() {
         ReadLockView v;
-        return ((v = readLockView) != null ? v :
-                (readLockView = new ReadLockView()));
+        if ((v = readLockView) != null) return v;
+        return readLockView = new ReadLockView();
     }
 
     /**
      * Returns a plain {@link Lock} view of this StampedLock in which
      * the {@link Lock#lock} method is mapped to {@link #writeLock},
      * and similarly for other methods. The returned Lock does not
-     * support a {@link Condition}; method {@link
-     * Lock#newCondition()} throws {@code
-     * UnsupportedOperationException}.
+     * support a {@link Condition}; method {@link Lock#newCondition()}
+     * throws {@code UnsupportedOperationException}.
      *
      * @return the lock
      */
     public Lock asWriteLock() {
         WriteLockView v;
-        return ((v = writeLockView) != null ? v :
-                (writeLockView = new WriteLockView()));
+        if ((v = writeLockView) != null) return v;
+        return writeLockView = new WriteLockView();
     }
 
     /**
@@ -870,8 +883,8 @@ public class StampedLock implements java.io.Serializable {
      */
     public ReadWriteLock asReadWriteLock() {
         ReadWriteLockView v;
-        return ((v = readWriteLockView) != null ? v :
-                (readWriteLockView = new ReadWriteLockView()));
+        if ((v = readWriteLockView) != null) return v;
+        return readWriteLockView = new ReadWriteLockView();
     }
 
     // view classes
@@ -917,35 +930,32 @@ public class StampedLock implements java.io.Serializable {
     // Needed because view-class lock methods throw away stamps.
 
     final void unstampedUnlockWrite() {
-        WNode h; long s;
+        long s;
         if (((s = state) & WBIT) == 0L)
             throw new IllegalMonitorStateException();
-        U.putLongVolatile(this, STATE, (s += WBIT) == 0L ? ORIGIN : s);
-        if ((h = whead) != null && h.status != 0)
-            release(h);
+        unlockWriteInternal(s);
     }
 
     final void unstampedUnlockRead() {
-        for (;;) {
-            long s, m; WNode h;
-            if ((m = (s = state) & ABITS) == 0L || m >= WBIT)
-                throw new IllegalMonitorStateException();
-            else if (m < RFULL) {
-                if (U.compareAndSwapLong(this, STATE, s, s - RUNIT)) {
+        long s, m; WNode h;
+        while ((m = (s = state) & RBITS) > 0L) {
+            if (m < RFULL) {
+                if (STATE.compareAndSet(this, s, s - RUNIT)) {
                     if (m == RUNIT && (h = whead) != null && h.status != 0)
                         release(h);
-                    break;
+                    return;
                 }
             }
             else if (tryDecReaderOverflow(s) != 0L)
-                break;
+                return;
         }
+        throw new IllegalMonitorStateException();
     }
 
     private void readObject(java.io.ObjectInputStream s)
         throws java.io.IOException, ClassNotFoundException {
         s.defaultReadObject();
-        U.putLongVolatile(this, STATE, ORIGIN); // reset to unlocked state
+        STATE.setVolatile(this, ORIGIN); // reset to unlocked state
     }
 
     // internals
@@ -961,15 +971,16 @@ public class StampedLock implements java.io.Serializable {
     private long tryIncReaderOverflow(long s) {
         // assert (s & ABITS) >= RFULL;
         if ((s & ABITS) == RFULL) {
-            if (U.compareAndSwapLong(this, STATE, s, s | RBITS)) {
+            if (STATE.compareAndSet(this, s, s | RBITS)) {
                 ++readerOverflow;
-                U.putLongVolatile(this, STATE, s);
+                STATE.setVolatile(this, s);
                 return s;
             }
         }
-        else if ((LockSupport.nextSecondarySeed() &
-                  OVERFLOW_YIELD_RATE) == 0)
+        else if ((LockSupport.nextSecondarySeed() & OVERFLOW_YIELD_RATE) == 0)
             Thread.yield();
+        else
+            Thread.onSpinWait();
         return 0L;
     }
 
@@ -982,7 +993,7 @@ public class StampedLock implements java.io.Serializable {
     private long tryDecReaderOverflow(long s) {
         // assert (s & ABITS) >= RFULL;
         if ((s & ABITS) == RFULL) {
-            if (U.compareAndSwapLong(this, STATE, s, s | RBITS)) {
+            if (STATE.compareAndSet(this, s, s | RBITS)) {
                 int r; long next;
                 if ((r = readerOverflow) > 0) {
                     readerOverflow = r - 1;
@@ -990,13 +1001,14 @@ public class StampedLock implements java.io.Serializable {
                 }
                 else
                     next = s - RUNIT;
-                U.putLongVolatile(this, STATE, next);
+                STATE.setVolatile(this, next);
                 return next;
             }
         }
-        else if ((LockSupport.nextSecondarySeed() &
-                  OVERFLOW_YIELD_RATE) == 0)
+        else if ((LockSupport.nextSecondarySeed() & OVERFLOW_YIELD_RATE) == 0)
             Thread.yield();
+        else
+            Thread.onSpinWait();
         return 0L;
     }
 
@@ -1010,14 +1022,14 @@ public class StampedLock implements java.io.Serializable {
     private void release(WNode h) {
         if (h != null) {
             WNode q; Thread w;
-            U.compareAndSwapInt(h, WSTATUS, WAITING, 0);
+            WSTATUS.compareAndSet(h, WAITING, 0);
             if ((q = h.next) == null || q.status == CANCELLED) {
                 for (WNode t = wtail; t != null && t != h; t = t.prev)
                     if (t.status <= 0)
                         q = t;
             }
             if (q != null && (w = q.thread) != null)
-                U.unpark(w);
+                LockSupport.unpark(w);
         }
     }
 
@@ -1035,25 +1047,25 @@ public class StampedLock implements java.io.Serializable {
         for (int spins = -1;;) { // spin while enqueuing
             long m, s, ns;
             if ((m = (s = state) & ABITS) == 0L) {
-                if (U.compareAndSwapLong(this, STATE, s, ns = s + WBIT))
+                if (STATE.compareAndSet(this, s, ns = s + WBIT))
                     return ns;
             }
             else if (spins < 0)
                 spins = (m == WBIT && wtail == whead) ? SPINS : 0;
             else if (spins > 0) {
-                if (LockSupport.nextSecondarySeed() >= 0)
-                    --spins;
+                --spins;
+                Thread.onSpinWait();
             }
             else if ((p = wtail) == null) { // initialize queue
                 WNode hd = new WNode(WMODE, null);
-                if (U.compareAndSwapObject(this, WHEAD, null, hd))
+                if (WHEAD.weakCompareAndSetVolatile(this, null, hd))
                     wtail = hd;
             }
             else if (node == null)
                 node = new WNode(WMODE, p);
             else if (node.prev != p)
                 node.prev = p;
-            else if (U.compareAndSwapObject(this, WTAIL, p, node)) {
+            else if (WTAIL.weakCompareAndSetVolatile(this, p, node)) {
                 p.next = node;
                 break;
             }
@@ -1067,11 +1079,10 @@ public class StampedLock implements java.io.Serializable {
                     spins = HEAD_SPINS;
                 else if (spins < MAX_HEAD_SPINS)
                     spins <<= 1;
-                for (int k = spins;;) { // spin at head
+                for (int k = spins; k > 0; --k) { // spin at head
                     long s, ns;
                     if (((s = state) & ABITS) == 0L) {
-                        if (U.compareAndSwapLong(this, STATE, s,
-                                                 ns = s + WBIT)) {
+                        if (STATE.compareAndSet(this, s, ns = s + WBIT)) {
                             whead = node;
                             node.prev = null;
                             if (wasInterrupted)
@@ -1079,17 +1090,16 @@ public class StampedLock implements java.io.Serializable {
                             return ns;
                         }
                     }
-                    else if (LockSupport.nextSecondarySeed() >= 0 &&
-                             --k <= 0)
-                        break;
+                    else
+                        Thread.onSpinWait();
                 }
             }
             else if (h != null) { // help release stale waiters
                 WNode c; Thread w;
                 while ((c = h.cowait) != null) {
-                    if (U.compareAndSwapObject(h, WCOWAIT, c, c.cowait) &&
+                    if (WCOWAIT.weakCompareAndSetVolatile(h, c, c.cowait) &&
                         (w = c.thread) != null)
-                        U.unpark(w);
+                        LockSupport.unpark(w);
                 }
             }
             if (whead == h) {
@@ -1098,7 +1108,7 @@ public class StampedLock implements java.io.Serializable {
                         (p = np).next = node;   // stale
                 }
                 else if ((ps = p.status) == 0)
-                    U.compareAndSwapInt(p, WSTATUS, 0, WAITING);
+                    WSTATUS.compareAndSet(p, 0, WAITING);
                 else if (ps == CANCELLED) {
                     if ((pp = p.prev) != null) {
                         node.prev = pp;
@@ -1112,13 +1122,15 @@ public class StampedLock implements java.io.Serializable {
                     else if ((time = deadline - System.nanoTime()) <= 0L)
                         return cancelWaiter(node, node, false);
                     Thread wt = Thread.currentThread();
-                    U.putObject(wt, PARKBLOCKER, this);
                     node.thread = wt;
                     if (p.status < 0 && (p != h || (state & ABITS) != 0L) &&
-                        whead == h && node.prev == p)
-                        U.park(false, time);  // emulate LockSupport.park
+                        whead == h && node.prev == p) {
+                        if (time == 0L)
+                            LockSupport.park(this);
+                        else
+                            LockSupport.parkNanos(this, time);
+                    }
                     node.thread = null;
-                    U.putObject(wt, PARKBLOCKER, null);
                     if (Thread.interrupted()) {
                         if (interruptible)
                             return cancelWaiter(node, node, true);
@@ -1146,7 +1158,7 @@ public class StampedLock implements java.io.Serializable {
             if ((h = whead) == (p = wtail)) {
                 for (long m, s, ns;;) {
                     if ((m = (s = state) & ABITS) < RFULL ?
-                        U.compareAndSwapLong(this, STATE, s, ns = s + RUNIT) :
+                        STATE.compareAndSet(this, s, ns = s + RUNIT) :
                         (m < WBIT && (ns = tryIncReaderOverflow(s)) != 0L)) {
                         if (wasInterrupted)
                             Thread.currentThread().interrupt();
@@ -1154,8 +1166,8 @@ public class StampedLock implements java.io.Serializable {
                     }
                     else if (m >= WBIT) {
                         if (spins > 0) {
-                            if (LockSupport.nextSecondarySeed() >= 0)
-                                --spins;
+                            --spins;
+                            Thread.onSpinWait();
                         }
                         else {
                             if (spins == 0) {
@@ -1170,7 +1182,7 @@ public class StampedLock implements java.io.Serializable {
             }
             if (p == null) { // initialize queue
                 WNode hd = new WNode(WMODE, null);
-                if (U.compareAndSwapObject(this, WHEAD, null, hd))
+                if (WHEAD.weakCompareAndSetVolatile(this, null, hd))
                     wtail = hd;
             }
             else if (node == null)
@@ -1178,27 +1190,25 @@ public class StampedLock implements java.io.Serializable {
             else if (h == p || p.mode != RMODE) {
                 if (node.prev != p)
                     node.prev = p;
-                else if (U.compareAndSwapObject(this, WTAIL, p, node)) {
+                else if (WTAIL.weakCompareAndSetVolatile(this, p, node)) {
                     p.next = node;
                     break;
                 }
             }
-            else if (!U.compareAndSwapObject(p, WCOWAIT,
-                                             node.cowait = p.cowait, node))
+            else if (!WCOWAIT.compareAndSet(p, node.cowait = p.cowait, node))
                 node.cowait = null;
             else {
                 for (;;) {
                     WNode pp, c; Thread w;
                     if ((h = whead) != null && (c = h.cowait) != null &&
-                        U.compareAndSwapObject(h, WCOWAIT, c, c.cowait) &&
+                        WCOWAIT.compareAndSet(h, c, c.cowait) &&
                         (w = c.thread) != null) // help release
-                        U.unpark(w);
+                        LockSupport.unpark(w);
                     if (h == (pp = p.prev) || h == p || pp == null) {
                         long m, s, ns;
                         do {
                             if ((m = (s = state) & ABITS) < RFULL ?
-                                U.compareAndSwapLong(this, STATE, s,
-                                                     ns = s + RUNIT) :
+                                STATE.compareAndSet(this, s, ns = s + RUNIT) :
                                 (m < WBIT &&
                                  (ns = tryIncReaderOverflow(s)) != 0L)) {
                                 if (wasInterrupted)
@@ -1221,13 +1231,15 @@ public class StampedLock implements java.io.Serializable {
                             return cancelWaiter(node, p, false);
                         }
                         Thread wt = Thread.currentThread();
-                        U.putObject(wt, PARKBLOCKER, this);
                         node.thread = wt;
                         if ((h != pp || (state & ABITS) == WBIT) &&
-                            whead == h && p.prev == pp)
-                            U.park(false, time);
+                            whead == h && p.prev == pp) {
+                            if (time == 0L)
+                                LockSupport.park(this);
+                            else
+                                LockSupport.parkNanos(this, time);
+                        }
                         node.thread = null;
-                        U.putObject(wt, PARKBLOCKER, null);
                         if (Thread.interrupted()) {
                             if (interruptible)
                                 return cancelWaiter(node, p, true);
@@ -1248,32 +1260,32 @@ public class StampedLock implements java.io.Serializable {
                 for (int k = spins;;) { // spin at head
                     long m, s, ns;
                     if ((m = (s = state) & ABITS) < RFULL ?
-                        U.compareAndSwapLong(this, STATE, s, ns = s + RUNIT) :
+                        STATE.compareAndSet(this, s, ns = s + RUNIT) :
                         (m < WBIT && (ns = tryIncReaderOverflow(s)) != 0L)) {
                         WNode c; Thread w;
                         whead = node;
                         node.prev = null;
                         while ((c = node.cowait) != null) {
-                            if (U.compareAndSwapObject(node, WCOWAIT,
-                                                       c, c.cowait) &&
+                            if (WCOWAIT.compareAndSet(node, c, c.cowait) &&
                                 (w = c.thread) != null)
-                                U.unpark(w);
+                                LockSupport.unpark(w);
                         }
                         if (wasInterrupted)
                             Thread.currentThread().interrupt();
                         return ns;
                     }
-                    else if (m >= WBIT &&
-                             LockSupport.nextSecondarySeed() >= 0 && --k <= 0)
+                    else if (m >= WBIT && --k <= 0)
                         break;
+                    else
+                        Thread.onSpinWait();
                 }
             }
             else if (h != null) {
                 WNode c; Thread w;
                 while ((c = h.cowait) != null) {
-                    if (U.compareAndSwapObject(h, WCOWAIT, c, c.cowait) &&
+                    if (WCOWAIT.compareAndSet(h, c, c.cowait) &&
                         (w = c.thread) != null)
-                        U.unpark(w);
+                        LockSupport.unpark(w);
                 }
             }
             if (whead == h) {
@@ -1282,7 +1294,7 @@ public class StampedLock implements java.io.Serializable {
                         (p = np).next = node;   // stale
                 }
                 else if ((ps = p.status) == 0)
-                    U.compareAndSwapInt(p, WSTATUS, 0, WAITING);
+                    WSTATUS.compareAndSet(p, 0, WAITING);
                 else if (ps == CANCELLED) {
                     if ((pp = p.prev) != null) {
                         node.prev = pp;
@@ -1296,14 +1308,16 @@ public class StampedLock implements java.io.Serializable {
                     else if ((time = deadline - System.nanoTime()) <= 0L)
                         return cancelWaiter(node, node, false);
                     Thread wt = Thread.currentThread();
-                    U.putObject(wt, PARKBLOCKER, this);
                     node.thread = wt;
                     if (p.status < 0 &&
                         (p != h || (state & ABITS) == WBIT) &&
-                        whead == h && node.prev == p)
-                        U.park(false, time);
+                        whead == h && node.prev == p) {
+                            if (time == 0L)
+                                LockSupport.park(this);
+                            else
+                                LockSupport.parkNanos(this, time);
+                    }
                     node.thread = null;
-                    U.putObject(wt, PARKBLOCKER, null);
                     if (Thread.interrupted()) {
                         if (interruptible)
                             return cancelWaiter(node, node, true);
@@ -1325,7 +1339,7 @@ public class StampedLock implements java.io.Serializable {
      * AbstractQueuedSynchronizer (see its detailed explanation in AQS
      * internal documentation).
      *
-     * @param node if nonnull, the waiter
+     * @param node if non-null, the waiter
      * @param group either node or the group node is cowaiting with
      * @param interrupted if already interrupted
      * @return INTERRUPTED if interrupted or Thread.interrupted, else zero
@@ -1337,7 +1351,7 @@ public class StampedLock implements java.io.Serializable {
             // unsplice cancelled nodes from group
             for (WNode p = group, q; (q = p.cowait) != null;) {
                 if (q.status == CANCELLED) {
-                    U.compareAndSwapObject(p, WCOWAIT, q, q.cowait);
+                    WCOWAIT.compareAndSet(p, q, q.cowait);
                     p = group; // restart
                 }
                 else
@@ -1346,7 +1360,7 @@ public class StampedLock implements java.io.Serializable {
             if (group == node) {
                 for (WNode r = group.cowait; r != null; r = r.cowait) {
                     if ((w = r.thread) != null)
-                        U.unpark(w);       // wake up uncancelled co-waiters
+                        LockSupport.unpark(w); // wake up uncancelled co-waiters
                 }
                 for (WNode pred = node.prev; pred != null; ) { // unsplice
                     WNode succ, pp;        // find valid successor
@@ -1357,23 +1371,23 @@ public class StampedLock implements java.io.Serializable {
                             if (t.status != CANCELLED)
                                 q = t;     // don't link if succ cancelled
                         if (succ == q ||   // ensure accurate successor
-                            U.compareAndSwapObject(node, WNEXT,
-                                                   succ, succ = q)) {
+                            WNEXT.compareAndSet(node, succ, succ = q)) {
                             if (succ == null && node == wtail)
-                                U.compareAndSwapObject(this, WTAIL, node, pred);
+                                WTAIL.compareAndSet(this, node, pred);
                             break;
                         }
                     }
                     if (pred.next == node) // unsplice pred link
-                        U.compareAndSwapObject(pred, WNEXT, node, succ);
+                        WNEXT.compareAndSet(pred, node, succ);
                     if (succ != null && (w = succ.thread) != null) {
+                        // wake up succ to observe new pred
                         succ.thread = null;
-                        U.unpark(w);       // wake up succ to observe new pred
+                        LockSupport.unpark(w);
                     }
                     if (pred.status != CANCELLED || (pp = pred.prev) == null)
                         break;
                     node.prev = pp;        // repeat if new pred wrong/cancelled
-                    U.compareAndSwapObject(pp, WNEXT, pred, succ);
+                    WNEXT.compareAndSet(pp, pred, succ);
                     pred = pp;
                 }
             }
@@ -1397,34 +1411,22 @@ public class StampedLock implements java.io.Serializable {
         return (interrupted || Thread.interrupted()) ? INTERRUPTED : 0L;
     }
 
-    // Unsafe mechanics
-    private static final jdk.internal.misc.Unsafe U = jdk.internal.misc.Unsafe.getUnsafe();
-    private static final long STATE;
-    private static final long WHEAD;
-    private static final long WTAIL;
-    private static final long WNEXT;
-    private static final long WSTATUS;
-    private static final long WCOWAIT;
-    private static final long PARKBLOCKER;
-
+    // VarHandle mechanics
+    private static final VarHandle STATE;
+    private static final VarHandle WHEAD;
+    private static final VarHandle WTAIL;
+    private static final VarHandle WNEXT;
+    private static final VarHandle WSTATUS;
+    private static final VarHandle WCOWAIT;
     static {
         try {
-            STATE = U.objectFieldOffset
-                (StampedLock.class.getDeclaredField("state"));
-            WHEAD = U.objectFieldOffset
-                (StampedLock.class.getDeclaredField("whead"));
-            WTAIL = U.objectFieldOffset
-                (StampedLock.class.getDeclaredField("wtail"));
-
-            WSTATUS = U.objectFieldOffset
-                (WNode.class.getDeclaredField("status"));
-            WNEXT = U.objectFieldOffset
-                (WNode.class.getDeclaredField("next"));
-            WCOWAIT = U.objectFieldOffset
-                (WNode.class.getDeclaredField("cowait"));
-
-            PARKBLOCKER = U.objectFieldOffset
-                (Thread.class.getDeclaredField("parkBlocker"));
+            MethodHandles.Lookup l = MethodHandles.lookup();
+            STATE = l.findVarHandle(StampedLock.class, "state", long.class);
+            WHEAD = l.findVarHandle(StampedLock.class, "whead", WNode.class);
+            WTAIL = l.findVarHandle(StampedLock.class, "wtail", WNode.class);
+            WSTATUS = l.findVarHandle(WNode.class, "status", int.class);
+            WNEXT = l.findVarHandle(WNode.class, "next", WNode.class);
+            WCOWAIT = l.findVarHandle(WNode.class, "cowait", WNode.class);
         } catch (ReflectiveOperationException e) {
             throw new Error(e);
         }

jdk/src/java.base/share/classes/java/util/concurrent/package-info.java

@@ -262,7 +262,6 @@
  *
  * </ul>
  *
- *
  * The methods of all classes in {@code java.util.concurrent} and its
  * subpackages extend these guarantees to higher-level
  * synchronization.  In particular:

jdk/src/java.httpclient/share/classes/java/net/http/AsyncConnection.java

@@ -20,7 +20,9 @@
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
+ * questions.
  */
+
 package java.net.http;
 
 import java.nio.ByteBuffer;

jdk/src/java.httpclient/share/classes/java/net/http/AsyncEvent.java

@@ -20,6 +20,7 @@
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
+ * questions.
  */
 
 package java.net.http;

jdk/src/java.httpclient/share/classes/java/net/http/AsyncSSLConnection.java

@@ -20,7 +20,9 @@
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
+ * questions.
  */
+
 package java.net.http;
 
 import java.io.IOException;

jdk/src/java.httpclient/share/classes/java/net/http/AsyncSSLDelegate.java

@@ -20,7 +20,9 @@
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
+ * questions.
  */
+
 package java.net.http;
 
 import java.io.Closeable;

jdk/src/java.httpclient/share/classes/java/net/http/AuthenticationFilter.java

@@ -20,7 +20,9 @@
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
+ * questions.
  */
+
 package java.net.http;
 
 import java.io.IOException;

jdk/src/java.httpclient/share/classes/java/net/http/BufferHandler.java

@@ -20,6 +20,7 @@
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
+ * questions.
  */
 
 package java.net.http;

jdk/src/java.httpclient/share/classes/java/net/http/ByteBufferConsumer.java

@@ -20,6 +20,7 @@
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
+ * questions.
  */
 
 package java.net.http;

jdk/src/java.httpclient/share/classes/java/net/http/ByteBufferGenerator.java

@@ -20,6 +20,7 @@
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
+ * questions.
  */
 
 package java.net.http;

jdk/src/java.httpclient/share/classes/java/net/http/CharsetToolkit.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2015, 2016, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -20,7 +20,9 @@
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
+ * questions.
  */
+
 package java.net.http;
 
 import java.nio.ByteBuffer;

jdk/src/java.httpclient/share/classes/java/net/http/ConnectionPool.java

@@ -20,7 +20,9 @@
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
+ * questions.
  */
+
 package java.net.http;
 
 import java.net.InetSocketAddress;

jdk/src/java.httpclient/share/classes/java/net/http/ContinuationFrame.java

@@ -20,6 +20,7 @@
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
+ * questions.
  */
 
 package java.net.http;

jdk/src/java.httpclient/share/classes/java/net/http/CookieFilter.java

@@ -20,6 +20,7 @@
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
+ * questions.
  */
 
 package java.net.http;