8022318: Document Spliterator characteristics and binding policy of java util concurrent collection impls

Co-authored-by: Martin Buchholz <martinrb@google.com>
Reviewed-by: chegar

jdk/src/share/classes/java/util/concurrent/ArrayBlockingQueue.java

@@ -757,12 +757,8 @@ public class ArrayBlockingQueue<E> extends AbstractQueue<E>
      * Returns an iterator over the elements in this queue in proper sequence.
      * The elements will be returned in order from first (head) to last (tail).
      *
-     * <p>The returned iterator is a "weakly consistent" iterator that
+     * <p>The returned iterator is
-     * will never throw {@link java.util.ConcurrentModificationException
+     * <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
-     * ConcurrentModificationException}, and guarantees to traverse
-     * elements as they existed upon construction of the iterator, and
-     * may (but is not guaranteed to) reflect any modifications
-     * subsequent to construction.
      *
      * @return an iterator over the elements in this queue in proper sequence
      */
@@ -1396,9 +1392,26 @@ public class ArrayBlockingQueue<E> extends AbstractQueue<E>
 //         }
     }
 
+    /**
+     * Returns a {@link Spliterator} over the elements in this queue.
+     *
+     * <p>The returned spliterator is
+     * <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
+     *
+     * <p>The {@code Spliterator} reports {@link Spliterator#CONCURRENT},
+     * {@link Spliterator#ORDERED}, and {@link Spliterator#NONNULL}.
+     *
+     * @implNote
+     * The {@code Spliterator} implements {@code trySplit} to permit limited
+     * parallelism.
+     *
+     * @return a {@code Spliterator} over the elements in this queue
+     * @since 1.8
+     */
     public Spliterator<E> spliterator() {
         return Spliterators.spliterator
             (this, Spliterator.ORDERED | Spliterator.NONNULL |
              Spliterator.CONCURRENT);
     }
+
 }

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

@@ -43,7 +43,6 @@ import java.util.AbstractMap;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Comparator;
-import java.util.ConcurrentModificationException;
 import java.util.Enumeration;
 import java.util.HashMap;
 import java.util.Hashtable;
@@ -94,14 +93,14 @@ import java.util.stream.Stream;
  * that key reporting the updated value.)  For aggregate operations
  * such as {@code putAll} and {@code clear}, concurrent retrievals may
  * reflect insertion or removal of only some entries.  Similarly,
- * Iterators and Enumerations return elements reflecting the state of
+ * Iterators, Spliterators and Enumerations return elements reflecting the
- * the hash table at some point at or since the creation of the
+ * state of the hash table at some point at or since the creation of the
  * iterator/enumeration.  They do <em>not</em> throw {@link
- * ConcurrentModificationException}.  However, iterators are designed
+ * java.util.ConcurrentModificationException ConcurrentModificationException}.
- * to be used by only one thread at a time.  Bear in mind that the
+ * However, iterators are designed to be used by only one thread at a time.
- * results of aggregate status methods including {@code size}, {@code
+ * Bear in mind that the results of aggregate status methods including
- * isEmpty}, and {@code containsValue} are typically useful only when
+ * {@code size}, {@code isEmpty}, and {@code containsValue} are typically
- * a map is not undergoing concurrent updates in other threads.
+ * useful only when a map is not undergoing concurrent updates in other threads.
  * Otherwise the results of these methods reflect transient states
  * that may be adequate for monitoring or estimation purposes, but not
  * for program control.
@@ -1200,11 +1199,11 @@ public class ConcurrentHashMap<K,V> extends AbstractMap<K,V>
      * operations.  It does not support the {@code add} or
      * {@code addAll} operations.
      *
-     * <p>The view's {@code iterator} is a "weakly consistent" iterator
+     * <p>The view's iterators and spliterators are
-     * that will never throw {@link ConcurrentModificationException},
+     * <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
-     * and guarantees to traverse elements as they existed upon
+     *
-     * construction of the iterator, and may (but is not guaranteed to)
+     * <p>The view's {@code spliterator} reports {@link Spliterator#CONCURRENT},
-     * reflect any modifications subsequent to construction.
+     * {@link Spliterator#DISTINCT}, and {@link Spliterator#NONNULL}.
      *
      * @return the set view
      */
@@ -1223,11 +1222,11 @@ public class ConcurrentHashMap<K,V> extends AbstractMap<K,V>
      * {@code retainAll}, and {@code clear} operations.  It does not
      * support the {@code add} or {@code addAll} operations.
      *
-     * <p>The view's {@code iterator} is a "weakly consistent" iterator
+     * <p>The view's iterators and spliterators are
-     * that will never throw {@link ConcurrentModificationException},
+     * <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
-     * and guarantees to traverse elements as they existed upon
+     *
-     * construction of the iterator, and may (but is not guaranteed to)
+     * <p>The view's {@code spliterator} reports {@link Spliterator#CONCURRENT}
-     * reflect any modifications subsequent to construction.
+     * and {@link Spliterator#NONNULL}.
      *
      * @return the collection view
      */
@@ -1245,11 +1244,11 @@ public class ConcurrentHashMap<K,V> extends AbstractMap<K,V>
      * {@code removeAll}, {@code retainAll}, and {@code clear}
      * operations.
      *
-     * <p>The view's {@code iterator} is a "weakly consistent" iterator
+     * <p>The view's iterators and spliterators are
-     * that will never throw {@link ConcurrentModificationException},
+     * <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
-     * and guarantees to traverse elements as they existed upon
+     *
-     * construction of the iterator, and may (but is not guaranteed to)
+     * <p>The view's {@code spliterator} reports {@link Spliterator#CONCURRENT},
-     * reflect any modifications subsequent to construction.
+     * {@link Spliterator#DISTINCT}, and {@link Spliterator#NONNULL}.
      *
      * @return the set view
      */
@@ -4308,12 +4307,12 @@ public class ConcurrentHashMap<K,V> extends AbstractMap<K,V>
         // implementations below rely on concrete classes supplying these
         // abstract methods
         /**
-         * Returns a "weakly consistent" iterator that will never
+         * Returns an iterator over the elements in this collection.
-         * throw {@link ConcurrentModificationException}, and
+         *
-         * guarantees to traverse elements as they existed upon
+         * <p>The returned iterator is
-         * construction of the iterator, and may (but is not
+         * <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
-         * guaranteed to) reflect any modifications subsequent to
+         *
-         * construction.
+         * @return an iterator over the elements in this collection
          */
         public abstract Iterator<E> iterator();
         public abstract boolean contains(Object o);

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

@@ -55,12 +55,8 @@ import java.util.function.Consumer;
  * Like most other concurrent collection implementations, this class
  * does not permit the use of {@code null} elements.
  *
- * <p>Iterators are <i>weakly consistent</i>, returning elements
+ * <p>Iterators and spliterators are
- * reflecting the state of the deque at some point at or since the
+ * <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
- * creation of the iterator.  They do <em>not</em> throw {@link
- * java.util.ConcurrentModificationException
- * ConcurrentModificationException}, and may proceed concurrently with
- * other operations.
  *
  * <p>Beware that, unlike in most collections, the {@code size} method
  * is <em>NOT</em> a constant-time operation. Because of the
@@ -1290,12 +1286,8 @@ public class ConcurrentLinkedDeque<E>
      * Returns an iterator over the elements in this deque in proper sequence.
      * The elements will be returned in order from first (head) to last (tail).
      *
-     * <p>The returned iterator is a "weakly consistent" iterator that
+     * <p>The returned iterator is
-     * will never throw {@link java.util.ConcurrentModificationException
+     * <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
-     * ConcurrentModificationException}, and guarantees to traverse
-     * elements as they existed upon construction of the iterator, and
-     * may (but is not guaranteed to) reflect any modifications
-     * subsequent to construction.
      *
      * @return an iterator over the elements in this deque in proper sequence
      */
@@ -1308,12 +1300,8 @@ public class ConcurrentLinkedDeque<E>
      * sequential order.  The elements will be returned in order from
      * last (tail) to first (head).
      *
-     * <p>The returned iterator is a "weakly consistent" iterator that
+     * <p>The returned iterator is
-     * will never throw {@link java.util.ConcurrentModificationException
+     * <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
-     * ConcurrentModificationException}, and guarantees to traverse
-     * elements as they existed upon construction of the iterator, and
-     * may (but is not guaranteed to) reflect any modifications
-     * subsequent to construction.
      *
      * @return an iterator over the elements in this deque in reverse order
      */
@@ -1493,6 +1481,22 @@ public class ConcurrentLinkedDeque<E>
         }
     }
 
+    /**
+     * Returns a {@link Spliterator} over the elements in this deque.
+     *
+     * <p>The returned spliterator is
+     * <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
+     *
+     * <p>The {@code Spliterator} reports {@link Spliterator#CONCURRENT},
+     * {@link Spliterator#ORDERED}, and {@link Spliterator#NONNULL}.
+     *
+     * @implNote
+     * The {@code Spliterator} implements {@code trySplit} to permit limited
+     * parallelism.
+     *
+     * @return a {@code Spliterator} over the elements in this deque
+     * @since 1.8
+     */
     public Spliterator<E> spliterator() {
         return new CLDSpliterator<E>(this);
     }
@@ -1500,6 +1504,8 @@ public class ConcurrentLinkedDeque<E>
     /**
      * Saves this deque to a stream (that is, serializes it).
      *
+     * @param s the stream
+     * @throws java.io.IOException if an I/O error occurs
      * @serialData All of the elements (each an {@code E}) in
      * the proper order, followed by a null
      */
@@ -1522,6 +1528,10 @@ public class ConcurrentLinkedDeque<E>
 
     /**
      * Reconstitutes this deque from a stream (that is, deserializes it).
+     * @param s the stream
+     * @throws ClassNotFoundException if the class of a serialized object
+     *         could not be found
+     * @throws java.io.IOException if an I/O error occurs
      */
     private void readObject(java.io.ObjectInputStream s)
         throws java.io.IOException, ClassNotFoundException {

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

@@ -654,12 +654,8 @@ public class ConcurrentLinkedQueue<E> extends AbstractQueue<E>
      * Returns an iterator over the elements in this queue in proper sequence.
      * The elements will be returned in order from first (head) to last (tail).
      *
-     * <p>The returned iterator is a "weakly consistent" iterator that
+     * <p>The returned iterator is
-     * will never throw {@link java.util.ConcurrentModificationException
+     * <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
-     * ConcurrentModificationException}, and guarantees to traverse
-     * elements as they existed upon construction of the iterator, and
-     * may (but is not guaranteed to) reflect any modifications
-     * subsequent to construction.
      *
      * @return an iterator over the elements in this queue in proper sequence
      */
@@ -749,6 +745,8 @@ public class ConcurrentLinkedQueue<E> extends AbstractQueue<E>
     /**
      * Saves this queue to a stream (that is, serializes it).
      *
+     * @param s the stream
+     * @throws java.io.IOException if an I/O error occurs
      * @serialData All of the elements (each an {@code E}) in
      * the proper order, followed by a null
      */
@@ -771,6 +769,10 @@ public class ConcurrentLinkedQueue<E> extends AbstractQueue<E>
 
     /**
      * Reconstitutes this queue from a stream (that is, deserializes it).
+     * @param s the stream
+     * @throws ClassNotFoundException if the class of a serialized object
+     *         could not be found
+     * @throws java.io.IOException if an I/O error occurs
      */
     private void readObject(java.io.ObjectInputStream s)
         throws java.io.IOException, ClassNotFoundException {
@@ -881,6 +883,23 @@ public class ConcurrentLinkedQueue<E> extends AbstractQueue<E>
         }
     }
 
+    /**
+     * Returns a {@link Spliterator} over the elements in this queue.
+     *
+     * <p>The returned spliterator is
+     * <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
+     *
+     * <p>The {@code Spliterator} reports {@link Spliterator#CONCURRENT},
+     * {@link Spliterator#ORDERED}, and {@link Spliterator#NONNULL}.
+     *
+     * @implNote
+     * The {@code Spliterator} implements {@code trySplit} to permit limited
+     * parallelism.
+     *
+     * @return a {@code Spliterator} over the elements in this queue
+     * @since 1.8
+     */
+    @Override
     public Spliterator<E> spliterator() {
         return new CLQSpliterator<E>(this);
     }

jdk/src/share/classes/java/util/concurrent/ConcurrentNavigableMap.java

@@ -120,11 +120,8 @@ public interface ConcurrentNavigableMap<K,V>
      * operations.  It does not support the {@code add} or {@code addAll}
      * operations.
      *
-     * <p>The view's {@code iterator} is a "weakly consistent" iterator
+     * <p>The view's iterators and spliterators are
-     * that will never throw {@link ConcurrentModificationException},
+     * <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
-     * and guarantees to traverse elements as they existed upon
-     * construction of the iterator, and may (but is not guaranteed to)
-     * reflect any modifications subsequent to construction.
      *
      * @return a navigable set view of the keys in this map
      */
@@ -141,11 +138,8 @@ public interface ConcurrentNavigableMap<K,V>
      * operations.  It does not support the {@code add} or {@code addAll}
      * operations.
      *
-     * <p>The view's {@code iterator} is a "weakly consistent" iterator
+     * <p>The view's iterators and spliterators are
-     * that will never throw {@link ConcurrentModificationException},
+     * <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
-     * and guarantees to traverse elements as they existed upon
-     * construction of the iterator, and may (but is not guaranteed to)
-     * reflect any modifications subsequent to construction.
      *
      * <p>This method is equivalent to method {@code navigableKeySet}.
      *
@@ -164,11 +158,8 @@ public interface ConcurrentNavigableMap<K,V>
      * operations.  It does not support the {@code add} or {@code addAll}
      * operations.
      *
-     * <p>The view's {@code iterator} is a "weakly consistent" iterator
+     * <p>The view's iterators and spliterators are
-     * that will never throw {@link ConcurrentModificationException},
+     * <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
-     * and guarantees to traverse elements as they existed upon
-     * construction of the iterator, and may (but is not guaranteed to)
-     * reflect any modifications subsequent to construction.
      *
      * @return a reverse order navigable set view of the keys in this map
      */

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

@@ -71,12 +71,13 @@ import java.util.function.Function;
  * {@code containsKey}, {@code get}, {@code put} and
  * {@code remove} operations and their variants.  Insertion, removal,
  * update, and access operations safely execute concurrently by
- * multiple threads.  Iterators are <i>weakly consistent</i>, returning
+ * multiple threads.
- * elements reflecting the state of the map at some point at or since
+ *
- * the creation of the iterator.  They do <em>not</em> throw {@link
+ * <p>Iterators and spliterators are
- * java.util.ConcurrentModificationException ConcurrentModificationException},
+ * <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
- * and may proceed concurrently with other operations. Ascending key ordered
+ *
- * views and their iterators are faster than descending ones.
+ * <p>Ascending key ordered views and their iterators are faster than
+ * descending ones.
  *
  * <p>All {@code Map.Entry} pairs returned by methods in this class
  * and its views represent snapshots of mappings at the time they were
@@ -1804,8 +1805,18 @@ public class ConcurrentSkipListMap<K,V> extends AbstractMap<K,V>
 
     /**
      * Returns a {@link NavigableSet} view of the keys contained in this map.
-     * The set's iterator returns the keys in ascending order.
+     *
-     * The set is backed by the map, so changes to the map are
+     * <p>The set's iterator returns the keys in ascending order.
+     * The set's spliterator additionally reports {@link Spliterator#CONCURRENT},
+     * {@link Spliterator#NONNULL}, {@link Spliterator#SORTED} and
+     * {@link Spliterator#ORDERED}, with an encounter order that is ascending
+     * key order.  The spliterator's comparator (see
+     * {@link java.util.Spliterator#getComparator()}) is {@code null} if
+     * the map's comparator (see {@link #comparator()}) is {@code null}.
+     * Otherwise, the spliterator's comparator is the same as or imposes the
+     * same total ordering as the map's comparator.
+     *
+     * <p>The set is backed by the map, so changes to the map are
      * reflected in the set, and vice-versa.  The set supports element
      * removal, which removes the corresponding mapping from the map,
      * via the {@code Iterator.remove}, {@code Set.remove},
@@ -1813,11 +1824,8 @@ public class ConcurrentSkipListMap<K,V> extends AbstractMap<K,V>
      * operations.  It does not support the {@code add} or {@code addAll}
      * operations.
      *
-     * <p>The view's {@code iterator} is a "weakly consistent" iterator that
+     * <p>The view's iterators and spliterators are
-     * will never throw {@link java.util.ConcurrentModificationException
+     * <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
-     * ConcurrentModificationException}, and guarantees to traverse elements
-     * as they existed upon construction of the iterator, and may (but is not
-     * guaranteed to) reflect any modifications subsequent to construction.
      *
      * <p>This method is equivalent to method {@code navigableKeySet}.
      *
@@ -1835,9 +1843,13 @@ public class ConcurrentSkipListMap<K,V> extends AbstractMap<K,V>
 
     /**
      * Returns a {@link Collection} view of the values contained in this map.
-     * The collection's iterator returns the values in ascending order
+     * <p>The collection's iterator returns the values in ascending order
-     * of the corresponding keys.
+     * of the corresponding keys. The collections's spliterator additionally
-     * The collection is backed by the map, so changes to the map are
+     * reports {@link Spliterator#CONCURRENT}, {@link Spliterator#NONNULL} and
+     * {@link Spliterator#ORDERED}, with an encounter order that is ascending
+     * order of the corresponding keys.
+     *
+     * <p>The collection is backed by the map, so changes to the map are
      * reflected in the collection, and vice-versa.  The collection
      * supports element removal, which removes the corresponding
      * mapping from the map, via the {@code Iterator.remove},
@@ -1845,11 +1857,8 @@ public class ConcurrentSkipListMap<K,V> extends AbstractMap<K,V>
      * {@code retainAll} and {@code clear} operations.  It does not
      * support the {@code add} or {@code addAll} operations.
      *
-     * <p>The view's {@code iterator} is a "weakly consistent" iterator that
+     * <p>The view's iterators and spliterators are
-     * will never throw {@link java.util.ConcurrentModificationException
+     * <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
-     * ConcurrentModificationException}, and guarantees to traverse elements
-     * as they existed upon construction of the iterator, and may (but is not
-     * guaranteed to) reflect any modifications subsequent to construction.
      */
     public Collection<V> values() {
         Values<V> vs = values;
@@ -1858,8 +1867,14 @@ public class ConcurrentSkipListMap<K,V> extends AbstractMap<K,V>
 
     /**
      * Returns a {@link Set} view of the mappings contained in this map.
-     * The set's iterator returns the entries in ascending key order.
+     *
-     * The set is backed by the map, so changes to the map are
+     * <p>The set's iterator returns the entries in ascending key order.  The
+     * set's spliterator additionally reports {@link Spliterator#CONCURRENT},
+     * {@link Spliterator#NONNULL}, {@link Spliterator#SORTED} and
+     * {@link Spliterator#ORDERED}, with an encounter order that is ascending
+     * key order.
+     *
+     * <p>The set is backed by the map, so changes to the map are
      * reflected in the set, and vice-versa.  The set supports element
      * removal, which removes the corresponding mapping from the map,
      * via the {@code Iterator.remove}, {@code Set.remove},
@@ -1867,15 +1882,12 @@ public class ConcurrentSkipListMap<K,V> extends AbstractMap<K,V>
      * operations.  It does not support the {@code add} or
      * {@code addAll} operations.
      *
-     * <p>The view's {@code iterator} is a "weakly consistent" iterator that
+     * <p>The view's iterators and spliterators are
-     * will never throw {@link java.util.ConcurrentModificationException
+     * <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
-     * ConcurrentModificationException}, and guarantees to traverse elements
-     * as they existed upon construction of the iterator, and may (but is not
-     * guaranteed to) reflect any modifications subsequent to construction.
      *
-     * <p>The {@code Map.Entry} elements returned by
+     * <p>The {@code Map.Entry} elements traversed by the {@code iterator}
-     * {@code iterator.next()} do <em>not</em> support the
+     * or {@code spliterator} do <em>not</em> support the {@code setValue}
-     * {@code setValue} operation.
+     * operation.
      *
      * @return a set view of the mappings contained in this map,
      *         sorted in ascending key order

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

@@ -57,12 +57,12 @@ import java.util.Spliterator;
  * cost for the {@code contains}, {@code add}, and {@code remove}
  * operations and their variants.  Insertion, removal, and access
  * operations safely execute concurrently by multiple threads.
- * Iterators are <i>weakly consistent</i>, returning elements
+ *
- * reflecting the state of the set at some point at or since the
+ * <p>Iterators and spliterators are
- * creation of the iterator.  They do <em>not</em> throw {@link
+ * <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
- * java.util.ConcurrentModificationException}, and may proceed
+ *
- * concurrently with other operations.  Ascending ordered views and
+ * <p>Ascending ordered views and their iterators are faster than
- * their iterators are faster than descending ones.
+ * descending ones.
  *
  * <p>Beware that, unlike in most collections, the {@code size}
  * method is <em>not</em> a constant-time operation. Because of the
@@ -480,6 +480,24 @@ public class ConcurrentSkipListSet<E>
         return new ConcurrentSkipListSet<E>(m.descendingMap());
     }
 
+    /**
+     * Returns a {@link Spliterator} over the elements in this set.
+     *
+     * <p>The {@code Spliterator} reports {@link Spliterator#CONCURRENT},
+     * {@link Spliterator#NONNULL}, {@link Spliterator#DISTINCT},
+     * {@link Spliterator#SORTED} and {@link Spliterator#ORDERED}, with an
+     * encounter order that is ascending order.  Overriding implementations
+     * should document the reporting of additional characteristic values.
+     *
+     * <p>The spliterator's comparator (see
+     * {@link java.util.Spliterator#getComparator()}) is {@code null} if
+     * the set's comparator (see {@link #comparator()}) is {@code null}.
+     * Otherwise, the spliterator's comparator is the same as or imposes the
+     * same total ordering as the set's comparator.
+     *
+     * @return a {@code Spliterator} over the elements in this set
+     * @since 1.8
+     */
     @SuppressWarnings("unchecked")
     public Spliterator<E> spliterator() {
         if (m instanceof ConcurrentSkipListMap)

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

@@ -952,6 +952,8 @@ public class CopyOnWriteArrayList<E>
     /**
      * Saves this list to a stream (that is, serializes it).
      *
+     * @param s the stream
+     * @throws java.io.IOException if an I/O error occurs
      * @serialData The length of the array backing the list is emitted
      *               (int), followed by all of its elements (each an Object)
      *               in the proper order.
@@ -972,6 +974,10 @@ public class CopyOnWriteArrayList<E>
 
     /**
      * Reconstitutes this list from a stream (that is, deserializes it).
+     * @param s the stream
+     * @throws ClassNotFoundException if the class of a serialized object
+     *         could not be found
+     * @throws java.io.IOException if an I/O error occurs
      */
     private void readObject(java.io.ObjectInputStream s)
         throws java.io.IOException, ClassNotFoundException {
@@ -1092,15 +1098,29 @@ public class CopyOnWriteArrayList<E>
      *
      * @throws IndexOutOfBoundsException {@inheritDoc}
      */
-    public ListIterator<E> listIterator(final int index) {
+    public ListIterator<E> listIterator(int index) {
         Object[] elements = getArray();
         int len = elements.length;
-        if (index<0 || index>len)
+        if (index < 0 || index > len)
             throw new IndexOutOfBoundsException("Index: "+index);
 
         return new COWIterator<E>(elements, index);
     }
 
+    /**
+     * Returns a {@link Spliterator} over the elements in this list.
+     *
+     * <p>The {@code Spliterator} reports {@link Spliterator#IMMUTABLE},
+     * {@link Spliterator#ORDERED}, {@link Spliterator#SIZED}, and
+     * {@link Spliterator#SUBSIZED}.
+     *
+     * <p>The spliterator provides a snapshot of the state of the list
+     * when the spliterator was constructed. No synchronization is needed while
+     * operating on the spliterator.
+     *
+     * @return a {@code Spliterator} over the elements in this list
+     * @since 1.8
+     */
     public Spliterator<E> spliterator() {
         return Spliterators.spliterator
             (getArray(), Spliterator.IMMUTABLE | Spliterator.ORDERED);
@@ -1257,7 +1277,7 @@ public class CopyOnWriteArrayList<E>
 
         // only call this holding l's lock
         private void rangeCheck(int index) {
-            if (index<0 || index>=size)
+            if (index < 0 || index >= size)
                 throw new IndexOutOfBoundsException("Index: "+index+
                                                     ",Size: "+size);
         }
@@ -1304,7 +1324,7 @@ public class CopyOnWriteArrayList<E>
             lock.lock();
             try {
                 checkForComodification();
-                if (index<0 || index>size)
+                if (index < 0 || index > size)
                     throw new IndexOutOfBoundsException();
                 l.add(index+offset, element);
                 expectedArray = l.getArray();
@@ -1361,12 +1381,12 @@ public class CopyOnWriteArrayList<E>
             }
         }
 
-        public ListIterator<E> listIterator(final int index) {
+        public ListIterator<E> listIterator(int index) {
             final ReentrantLock lock = l.lock;
             lock.lock();
             try {
                 checkForComodification();
-                if (index<0 || index>size)
+                if (index < 0 || index > size)
                     throw new IndexOutOfBoundsException("Index: "+index+
                                                         ", Size: "+size);
                 return new COWSubListIterator<E>(l, index, offset, size);
@@ -1380,7 +1400,7 @@ public class CopyOnWriteArrayList<E>
             lock.lock();
             try {
                 checkForComodification();
-                if (fromIndex<0 || toIndex>size)
+                if (fromIndex < 0 || toIndex > size)
                     throw new IndexOutOfBoundsException();
                 return new COWSubList<E>(l, fromIndex + offset,
                                          toIndex + offset);
@@ -1580,6 +1600,7 @@ public class CopyOnWriteArrayList<E>
             return Spliterators.spliterator
                 (a, lo, hi, Spliterator.IMMUTABLE | Spliterator.ORDERED);
         }
+
     }
 
     private static class COWSubListIterator<E> implements ListIterator<E> {

jdk/src/share/classes/java/util/concurrent/CopyOnWriteArraySet.java

@@ -404,6 +404,21 @@ public class CopyOnWriteArraySet<E> extends AbstractSet<E>
         al.forEach(action);
     }
 
+    /**
+     * Returns a {@link Spliterator} over the elements in this set in the order
+     * in which these elements were added.
+     *
+     * <p>The {@code Spliterator} reports {@link Spliterator#IMMUTABLE},
+     * {@link Spliterator#DISTINCT}, {@link Spliterator#SIZED}, and
+     * {@link Spliterator#SUBSIZED}.
+     *
+     * <p>The spliterator provides a snapshot of the state of the set
+     * when the spliterator was constructed. No synchronization is needed while
+     * operating on the spliterator.
+     *
+     * @return a {@code Spliterator} over the elements in this set
+     * @since 1.8
+     */
     public Spliterator<E> spliterator() {
         return Spliterators.spliterator
             (al.getArray(), Spliterator.IMMUTABLE | Spliterator.DISTINCT);

jdk/src/share/classes/java/util/concurrent/DelayQueue.java

@@ -512,12 +512,8 @@ public class DelayQueue<E extends Delayed> extends AbstractQueue<E>
      * unexpired) in this queue. The iterator does not return the
      * elements in any particular order.
      *
-     * <p>The returned iterator is a "weakly consistent" iterator that
+     * <p>The returned iterator is
-     * will never throw {@link java.util.ConcurrentModificationException
+     * <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
-     * ConcurrentModificationException}, and guarantees to traverse
-     * elements as they existed upon construction of the iterator, and
-     * may (but is not guaranteed to) reflect any modifications
-     * subsequent to construction.
      *
      * @return an iterator over the elements in this queue
      */

jdk/src/share/classes/java/util/concurrent/LinkedBlockingDeque.java

@@ -1008,12 +1008,8 @@ public class LinkedBlockingDeque<E>
      * Returns an iterator over the elements in this deque in proper sequence.
      * The elements will be returned in order from first (head) to last (tail).
      *
-     * <p>The returned iterator is a "weakly consistent" iterator that
+     * <p>The returned iterator is
-     * will never throw {@link java.util.ConcurrentModificationException
+     * <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
-     * ConcurrentModificationException}, and guarantees to traverse
-     * elements as they existed upon construction of the iterator, and
-     * may (but is not guaranteed to) reflect any modifications
-     * subsequent to construction.
      *
      * @return an iterator over the elements in this deque in proper sequence
      */
@@ -1026,12 +1022,8 @@ public class LinkedBlockingDeque<E>
      * sequential order.  The elements will be returned in order from
      * last (tail) to first (head).
      *
-     * <p>The returned iterator is a "weakly consistent" iterator that
+     * <p>The returned iterator is
-     * will never throw {@link java.util.ConcurrentModificationException
+     * <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
-     * ConcurrentModificationException}, and guarantees to traverse
-     * elements as they existed upon construction of the iterator, and
-     * may (but is not guaranteed to) reflect any modifications
-     * subsequent to construction.
      *
      * @return an iterator over the elements in this deque in reverse order
      */
@@ -1270,6 +1262,22 @@ public class LinkedBlockingDeque<E>
         }
     }
 
+    /**
+     * Returns a {@link Spliterator} over the elements in this deque.
+     *
+     * <p>The returned spliterator is
+     * <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
+     *
+     * <p>The {@code Spliterator} reports {@link Spliterator#CONCURRENT},
+     * {@link Spliterator#ORDERED}, and {@link Spliterator#NONNULL}.
+     *
+     * @implNote
+     * The {@code Spliterator} implements {@code trySplit} to permit limited
+     * parallelism.
+     *
+     * @return a {@code Spliterator} over the elements in this deque
+     * @since 1.8
+     */
     public Spliterator<E> spliterator() {
         return new LBDSpliterator<E>(this);
     }
@@ -1277,6 +1285,8 @@ public class LinkedBlockingDeque<E>
     /**
      * Saves this deque to a stream (that is, serializes it).
      *
+     * @param s the stream
+     * @throws java.io.IOException if an I/O error occurs
      * @serialData The capacity (int), followed by elements (each an
      * {@code Object}) in the proper order, followed by a null
      */
@@ -1299,6 +1309,10 @@ public class LinkedBlockingDeque<E>
 
     /**
      * Reconstitutes this deque from a stream (that is, deserializes it).
+     * @param s the stream
+     * @throws ClassNotFoundException if the class of a serialized object
+     *         could not be found
+     * @throws java.io.IOException if an I/O error occurs
      */
     private void readObject(java.io.ObjectInputStream s)
         throws java.io.IOException, ClassNotFoundException {

jdk/src/share/classes/java/util/concurrent/LinkedBlockingQueue.java

@@ -766,12 +766,8 @@ public class LinkedBlockingQueue<E> extends AbstractQueue<E>
      * Returns an iterator over the elements in this queue in proper sequence.
      * The elements will be returned in order from first (head) to last (tail).
      *
-     * <p>The returned iterator is a "weakly consistent" iterator that
+     * <p>The returned iterator is
-     * will never throw {@link java.util.ConcurrentModificationException
+     * <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
-     * ConcurrentModificationException}, and guarantees to traverse
-     * elements as they existed upon construction of the iterator, and
-     * may (but is not guaranteed to) reflect any modifications
-     * subsequent to construction.
      *
      * @return an iterator over the elements in this queue in proper sequence
      */
@@ -973,6 +969,22 @@ public class LinkedBlockingQueue<E> extends AbstractQueue<E>
         }
     }
 
+    /**
+     * Returns a {@link Spliterator} over the elements in this queue.
+     *
+     * <p>The returned spliterator is
+     * <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
+     *
+     * <p>The {@code Spliterator} reports {@link Spliterator#CONCURRENT},
+     * {@link Spliterator#ORDERED}, and {@link Spliterator#NONNULL}.
+     *
+     * @implNote
+     * The {@code Spliterator} implements {@code trySplit} to permit limited
+     * parallelism.
+     *
+     * @return a {@code Spliterator} over the elements in this queue
+     * @since 1.8
+     */
     public Spliterator<E> spliterator() {
         return new LBQSpliterator<E>(this);
     }
@@ -980,6 +992,8 @@ public class LinkedBlockingQueue<E> extends AbstractQueue<E>
     /**
      * Saves this queue to a stream (that is, serializes it).
      *
+     * @param s the stream
+     * @throws java.io.IOException if an I/O error occurs
      * @serialData The capacity is emitted (int), followed by all of
      * its elements (each an {@code Object}) in the proper order,
      * followed by a null
@@ -1005,6 +1019,10 @@ public class LinkedBlockingQueue<E> extends AbstractQueue<E>
 
     /**
      * Reconstitutes this queue from a stream (that is, deserializes it).
+     * @param s the stream
+     * @throws ClassNotFoundException if the class of a serialized object
+     *         could not be found
+     * @throws java.io.IOException if an I/O error occurs
      */
     private void readObject(java.io.ObjectInputStream s)
         throws java.io.IOException, ClassNotFoundException {

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

@@ -40,6 +40,7 @@ import java.util.Collection;
 import java.util.Iterator;
 import java.util.NoSuchElementException;
 import java.util.Queue;
+import java.util.concurrent.TimeUnit;
 import java.util.concurrent.locks.LockSupport;
 import java.util.Spliterator;
 import java.util.Spliterators;
@@ -1018,6 +1019,22 @@ public class LinkedTransferQueue<E> extends AbstractQueue<E>
         }
     }
 
+    /**
+     * Returns a {@link Spliterator} over the elements in this queue.
+     *
+     * <p>The returned spliterator is
+     * <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
+     *
+     * <p>The {@code Spliterator} reports {@link Spliterator#CONCURRENT},
+     * {@link Spliterator#ORDERED}, and {@link Spliterator#NONNULL}.
+     *
+     * @implNote
+     * The {@code Spliterator} implements {@code trySplit} to permit limited
+     * parallelism.
+     *
+     * @return a {@code Spliterator} over the elements in this queue
+     * @since 1.8
+     */
     public Spliterator<E> spliterator() {
         return new LTQSpliterator<E>(this);
     }
@@ -1301,12 +1318,8 @@ public class LinkedTransferQueue<E> extends AbstractQueue<E>
      * Returns an iterator over the elements in this queue in proper sequence.
      * The elements will be returned in order from first (head) to last (tail).
      *
-     * <p>The returned iterator is a "weakly consistent" iterator that
+     * <p>The returned iterator is
-     * will never throw {@link java.util.ConcurrentModificationException
+     * <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
-     * ConcurrentModificationException}, and guarantees to traverse
-     * elements as they existed upon construction of the iterator, and
-     * may (but is not guaranteed to) reflect any modifications
-     * subsequent to construction.
      *
      * @return an iterator over the elements in this queue in proper sequence
      */
@@ -1407,6 +1420,8 @@ public class LinkedTransferQueue<E> extends AbstractQueue<E>
     /**
      * Saves this queue to a stream (that is, serializes it).
      *
+     * @param s the stream
+     * @throws java.io.IOException if an I/O error occurs
      * @serialData All of the elements (each an {@code E}) in
      * the proper order, followed by a null
      */
@@ -1421,6 +1436,10 @@ public class LinkedTransferQueue<E> extends AbstractQueue<E>
 
     /**
      * Reconstitutes this queue from a stream (that is, deserializes it).
+     * @param s the stream
+     * @throws ClassNotFoundException if the class of a serialized object
+     *         could not be found
+     * @throws java.io.IOException if an I/O error occurs
      */
     private void readObject(java.io.ObjectInputStream s)
         throws java.io.IOException, ClassNotFoundException {

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

@@ -229,7 +229,7 @@ public class PriorityBlockingQueue<E> extends AbstractQueue<E>
     /**
      * Creates a {@code PriorityBlockingQueue} containing the elements
      * in the specified collection.  If the specified collection is a
-     * {@link SortedSet} or a {@link PriorityQueue},  this
+     * {@link SortedSet} or a {@link PriorityQueue}, this
      * priority queue will be ordered according to the same ordering.
      * Otherwise, this priority queue will be ordered according to the
      * {@linkplain Comparable natural ordering} of its elements.
@@ -864,12 +864,8 @@ public class PriorityBlockingQueue<E> extends AbstractQueue<E>
      * Returns an iterator over the elements in this queue. The
      * iterator does not return the elements in any particular order.
      *
-     * <p>The returned iterator is a "weakly consistent" iterator that
+     * <p>The returned iterator is
-     * will never throw {@link java.util.ConcurrentModificationException
+     * <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
-     * ConcurrentModificationException}, and guarantees to traverse
-     * elements as they existed upon construction of the iterator, and
-     * may (but is not guaranteed to) reflect any modifications
-     * subsequent to construction.
      *
      * @return an iterator over the elements in this queue
      */
@@ -915,6 +911,9 @@ public class PriorityBlockingQueue<E> extends AbstractQueue<E>
      * For compatibility with previous version of this class, elements
      * are first copied to a java.util.PriorityQueue, which is then
      * serialized.
+     *
+     * @param s the stream
+     * @throws java.io.IOException if an I/O error occurs
      */
     private void writeObject(java.io.ObjectOutputStream s)
         throws java.io.IOException {
@@ -932,6 +931,10 @@ public class PriorityBlockingQueue<E> extends AbstractQueue<E>
 
     /**
      * Reconstitutes this queue from a stream (that is, deserializes it).
+     * @param s the stream
+     * @throws ClassNotFoundException if the class of a serialized object
+     *         could not be found
+     * @throws java.io.IOException if an I/O error occurs
      */
     private void readObject(java.io.ObjectInputStream s)
         throws java.io.IOException, ClassNotFoundException {
@@ -1005,6 +1008,21 @@ public class PriorityBlockingQueue<E> extends AbstractQueue<E>
         }
     }
 
+    /**
+     * Returns a {@link Spliterator} over the elements in this queue.
+     *
+     * <p>The returned spliterator is
+     * <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
+     *
+     * <p>The {@code Spliterator} reports {@link Spliterator#SIZED} and
+     * {@link Spliterator#NONNULL}.
+     *
+     * @implNote
+     * The {@code Spliterator} additionally reports {@link Spliterator#SUBSIZED}.
+     *
+     * @return a {@code Spliterator} over the elements in this queue
+     * @since 1.8
+     */
     public Spliterator<E> spliterator() {
         return new PBQSpliterator<E>(this, null, 0, -1);
     }

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

@@ -38,6 +38,8 @@ package java.util.concurrent;
 import java.util.concurrent.locks.LockSupport;
 import java.util.concurrent.locks.ReentrantLock;
 import java.util.*;
+import java.util.Spliterator;
+import java.util.Spliterators;
 
 /**
  * A {@linkplain BlockingQueue blocking queue} in which each insert
@@ -1062,21 +1064,17 @@ public class SynchronousQueue<E> extends AbstractQueue<E>
      *
      * @return an empty iterator
      */
-    @SuppressWarnings("unchecked")
     public Iterator<E> iterator() {
-        return (Iterator<E>) EmptyIterator.EMPTY_ITERATOR;
+        return Collections.emptyIterator();
-    }
-
-    // Replicated from a previous version of Collections
-    private static class EmptyIterator<E> implements Iterator<E> {
-        static final EmptyIterator<Object> EMPTY_ITERATOR
-            = new EmptyIterator<Object>();
-
-        public boolean hasNext() { return false; }
-        public E next() { throw new NoSuchElementException(); }
-        public void remove() { throw new IllegalStateException(); }
     }
 
+    /**
+     * Returns an empty spliterator in which calls to
+     * {@link java.util.Spliterator#trySplit()} always return {@code null}.
+     *
+     * @return an empty spliterator
+     * @since 1.8
+     */
     public Spliterator<E> spliterator() {
         return Spliterators.emptySpliterator();
     }
@@ -1163,6 +1161,8 @@ public class SynchronousQueue<E> extends AbstractQueue<E>
 
     /**
      * Saves this queue to a stream (that is, serializes it).
+     * @param s the stream
+     * @throws java.io.IOException if an I/O error occurs
      */
     private void writeObject(java.io.ObjectOutputStream s)
         throws java.io.IOException {
@@ -1182,8 +1182,12 @@ public class SynchronousQueue<E> extends AbstractQueue<E>
 
     /**
      * Reconstitutes this queue from a stream (that is, deserializes it).
+     * @param s the stream
+     * @throws ClassNotFoundException if the class of a serialized object
+     *         could not be found
+     * @throws java.io.IOException if an I/O error occurs
      */
-    private void readObject(final java.io.ObjectInputStream s)
+    private void readObject(java.io.ObjectInputStream s)
         throws java.io.IOException, ClassNotFoundException {
         s.defaultReadObject();
         if (waitingProducers instanceof FifoWaitQueue)

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

@@ -210,13 +210,19 @@
  * collections are unshared, or are accessible only when
  * holding other locks.
  *
- * <p>Most concurrent Collection implementations (including most
+ * <p id="Weakly">Most concurrent Collection implementations
- * Queues) also differ from the usual java.util conventions in that
+ * (including most Queues) also differ from the usual {@code java.util}
- * their Iterators provide <em>weakly consistent</em> rather than
+ * conventions in that their {@linkplain java.util.Iterator Iterators}
- * fast-fail traversal.  A weakly consistent iterator is thread-safe,
+ * and {@linkplain java.util.Spliterator Spliterators} provide
- * but does not necessarily freeze the collection while iterating, so
+ * <em>weakly consistent</em> rather than fast-fail traversal:
- * it may (or may not) reflect any updates since the iterator was
+ * <ul>
- * created.
+ * <li>they may proceed concurrently with other operations
+ * <li>they will never throw {@link java.util.ConcurrentModificationException
+ * ConcurrentModificationException}
+ * <li>they are guaranteed to traverse elements as they existed upon
+ * construction exactly once, and may (but are not guaranteed to)
+ * reflect any modifications subsequent to construction.
+ * </ul>
  *
  * <h2 id="MemoryVisibility">Memory Consistency Properties</h2>
  *