8131600: heapdump/JMapHeap EXCEPTION_ACCESS_VIOLATION

Reviewed-by: mgerdin, kbarrett, tschatzl

hotspot/src/share/vm/prims/jvmtiTagMap.cpp

@@ -2824,7 +2824,7 @@ inline bool VM_HeapWalkOperation::iterate_over_class(oop java_class) {
   if (klass->oop_is_instance()) {
     InstanceKlass* ik = InstanceKlass::cast(klass);
 
-    // ignore the class if it's has been initialized yet
+    // Ignore the class if it hasn't been initialized yet
     if (!ik->is_linked()) {
       return true;
     }

hotspot/src/share/vm/services/heapDumper.cpp

@@ -899,6 +899,11 @@ void DumperSupport::dump_class_and_array_classes(DumpWriter* writer, Klass* k) {
   assert(klass->oop_is_instance(), "not an InstanceKlass");
   InstanceKlass* ik = (InstanceKlass*)klass;
 
+  // Ignore the class if it hasn't been initialized yet
+  if (!ik->is_linked()) {
+    return;
+  }
+
   writer->write_u1(HPROF_GC_CLASS_DUMP);
 
   // class ID