8005051: optimized defaults for Iterator.forEachRemaining

Reviewed-by: alanb, mduigou, psandoz, ulfzibis
Contributed-by: NAkhil Arora <akhil.arora@oracle.com>

src/share/classes/java/util/ArrayList.java

@@ -29,10 +29,6 @@ import java.util.function.Consumer;
 import java.util.function.Predicate;
 import java.util.function.UnaryOperator;
 
-import java.util.function.Consumer;
-import java.util.function.Predicate;
-import java.util.function.UnaryOperator;
-
 /**
  * Resizable-array implementation of the <tt>List</tt> interface.  Implements
  * all optional list operations, and permits all elements, including

src/share/classes/java/util/LinkedList.java

@@ -957,6 +957,7 @@ public class LinkedList<E>
                 next = next.next;
                 nextIndex++;
             }
+            lastReturned = next;
             checkForComodification();
         }
 

src/share/classes/java/util/Vector.java

@@ -29,8 +29,6 @@ import java.util.function.Consumer;
 import java.util.function.Predicate;
 import java.util.function.UnaryOperator;
 
-import java.util.function.Consumer;
-
 /**
  * The {@code Vector} class implements a growable array of
  * objects. Like an array, it contains components that can be
@@ -1161,7 +1159,7 @@ public class Vector<E>
         public void forEachRemaining(Consumer<? super E> action) {
             Objects.requireNonNull(action);
             synchronized (Vector.this) {
-                final int size = Vector.this.elementCount;
+                final int size = elementCount;
                 int i = cursor;
                 if (i >= size) {
                     return;

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

@@ -1059,6 +1059,17 @@ public class CopyOnWriteArrayList<E>
         public void add(E e) {
             throw new UnsupportedOperationException();
         }
+
+        @Override
+        @SuppressWarnings("unchecked")
+        public void forEachRemaining(Consumer<? super E> action) {
+            Objects.requireNonNull(action);
+            final int size = snapshot.length;
+            for (int i=cursor; i < size; i++) {
+                action.accept((E) snapshot[i]);
+            }
+            cursor = size;
+        }
     }
 
     /**
@@ -1367,6 +1378,15 @@ public class CopyOnWriteArrayList<E>
         public void add(E e) {
             throw new UnsupportedOperationException();
         }
+
+        @Override
+        @SuppressWarnings("unchecked")
+        public void forEachRemaining(Consumer<? super E> action) {
+            Objects.requireNonNull(action);
+            while (nextIndex() < size) {
+                action.accept(it.next());
+            }
+        }
     }
 
     // Support for resetting lock while deserializing