--- jsr166/src/main/java/util/ArrayDeque.java	2016/11/21 15:30:44	1.121
+++ jsr166/src/main/java/util/ArrayDeque.java	2017/05/06 06:49:45	1.128
@@ -50,7 +50,7 @@ import java.util.function.UnaryOperator;
  * Iterator} interfaces.
  *
  * <p>This class is a member of the
- * <a href="{@docRoot}/../technotes/guides/collections/index.html">
+ * <a href="{@docRoot}/java/util/package-summary.html#CollectionsFramework">
  * Java Collections Framework</a>.
  *
  * @author  Josh Bloch and Doug Lea
@@ -117,16 +117,16 @@ public class ArrayDeque<E> extends Abstr
         if (jump < needed
             || (newCapacity = (oldCapacity + jump)) - MAX_ARRAY_SIZE > 0)
             newCapacity = newCapacity(needed, jump);
-        elements = Arrays.copyOf(elements, newCapacity);
+        final Object[] es = elements = Arrays.copyOf(elements, newCapacity);
         // Exceptionally, here tail == head needs to be disambiguated
-        if (tail < head || (tail == head && elements[head] != null)) {
+        if (tail < head || (tail == head && es[head] != null)) {
             // wrap around; slide first leg forward to end of array
             int newSpace = newCapacity - oldCapacity;
-            System.arraycopy(elements, head,
-                             elements, head + newSpace,
+            System.arraycopy(es, head,
+                             es, head + newSpace,
                              oldCapacity - head);
-            Arrays.fill(elements, head, head + newSpace, null);
-            head += newSpace;
+            for (int i = head, to = (head += newSpace); i < to; i++)
+                es[i] = null;
         }
         // checkInvariants();
     }
@@ -235,7 +235,7 @@ public class ArrayDeque<E> extends Abstr
      * @return index 0 <= i < modulus
      */
     static final int add(int i, int distance, int modulus) {
-        if ((i += distance) - modulus >= 0) distance -= modulus;
+        if ((i += distance) - modulus >= 0) i -= modulus;
         return i;
     }
 
@@ -520,8 +520,8 @@ public class ArrayDeque<E> extends Abstr
     /**
      * Retrieves and removes the head of the queue represented by this deque.
      *
-     * This method differs from {@link #poll poll} only in that it throws an
-     * exception if this deque is empty.
+     * This method differs from {@link #poll() poll()} only in that it
+     * throws an exception if this deque is empty.
      *
      * <p>This method is equivalent to {@link #removeFirst}.
      *
@@ -710,8 +710,7 @@ public class ArrayDeque<E> extends Abstr
                 throw new NoSuchElementException();
             final Object[] es = elements;
             E e = nonNullElementAt(es, cursor);
-            lastRet = cursor;
-            cursor = inc(cursor, es.length);
+            cursor = inc(lastRet = cursor, es.length);
             remaining--;
             return e;
         }
@@ -759,8 +758,7 @@ public class ArrayDeque<E> extends Abstr
                 throw new NoSuchElementException();
             final Object[] es = elements;
             E e = nonNullElementAt(es, cursor);
-            lastRet = cursor;
-            cursor = dec(cursor, es.length);
+            cursor = dec(lastRet = cursor, es.length);
             remaining--;
             return e;
         }
@@ -822,6 +820,8 @@ public class ArrayDeque<E> extends Abstr
 
         /** Constructs spliterator over the given range. */
         DeqSpliterator(int origin, int fence) {
+            // assert 0 <= origin && origin < elements.length;
+            // assert 0 <= fence && fence < elements.length;
             this.cursor = origin;
             this.fence = fence;
         }
@@ -888,6 +888,9 @@ public class ArrayDeque<E> extends Abstr
         }
     }
 
+    /**
+     * @throws NullPointerException {@inheritDoc}
+     */
     public void forEach(Consumer<? super E> action) {
         Objects.requireNonNull(action);
         final Object[] es = elements;
@@ -1076,11 +1079,14 @@ public class ArrayDeque<E> extends Abstr
 
     /**
      * Nulls out slots starting at array index i, upto index end.
+     * Condition i == end means "empty" - nothing to do.
      */
     private static void circularClear(Object[] es, int i, int end) {
+        // assert 0 <= i && i < es.length;
+        // assert 0 <= end && end < es.length;
         for (int to = (i <= end) ? end : es.length;
              ; i = 0, to = end) {
-            Arrays.fill(es, i, to, null);
+            for (; i < to; i++) es[i] = null;
             if (to == end) break;
         }
     }
@@ -1244,8 +1250,8 @@ public class ArrayDeque<E> extends Abstr
         // head == tail disambiguates to "empty".
         try {
             int capacity = elements.length;
-            // assert head >= 0 && head < capacity;
-            // assert tail >= 0 && tail < capacity;
+            // assert 0 <= head && head < capacity;
+            // assert 0 <= tail && tail < capacity;
             // assert capacity > 0;
             // assert size() < capacity;
             // assert head == tail || elements[head] != null;