--- jsr166/src/main/java/util/ArrayDeque.java	2017/05/31 19:01:08	1.129
+++ jsr166/src/main/java/util/ArrayDeque.java	2018/06/30 22:35:55	1.134
@@ -9,6 +9,7 @@ import java.io.Serializable;
 import java.util.function.Consumer;
 import java.util.function.Predicate;
 import java.util.function.UnaryOperator;
+import jdk.internal.misc.SharedSecrets;
 
 /**
  * Resizable-array implementation of the {@link Deque} interface.  Array
@@ -180,7 +181,7 @@ public class ArrayDeque<E> extends Abstr
      * sufficient to hold 16 elements.
      */
     public ArrayDeque() {
-        elements = new Object[16];
+        elements = new Object[16 + 1];
     }
 
     /**
@@ -208,11 +209,11 @@ public class ArrayDeque<E> extends Abstr
      */
     public ArrayDeque(Collection<? extends E> c) {
         this(c.size());
-        addAll(c);
+        copyElements(c);
     }
 
     /**
-     * Increments i, mod modulus.
+     * Circularly increments i, mod modulus.
      * Precondition and postcondition: 0 <= i < modulus.
      */
     static final int inc(int i, int modulus) {
@@ -221,7 +222,7 @@ public class ArrayDeque<E> extends Abstr
     }
 
     /**
-     * Decrements i, mod modulus.
+     * Circularly decrements i, mod modulus.
      * Precondition and postcondition: 0 <= i < modulus.
      */
     static final int dec(int i, int modulus) {
@@ -234,7 +235,7 @@ public class ArrayDeque<E> extends Abstr
      * Precondition: 0 <= i < modulus, 0 <= distance <= modulus.
      * @return index 0 <= i < modulus
      */
-    static final int add(int i, int distance, int modulus) {
+    static final int inc(int i, int distance, int modulus) {
         if ((i += distance) - modulus >= 0) i -= modulus;
         return i;
     }
@@ -244,7 +245,7 @@ public class ArrayDeque<E> extends Abstr
      * Index i must be logically ahead of index j.
      * Precondition: 0 <= i < modulus, 0 <= j < modulus.
      * @return the "circular distance" from j to i; corner case i == j
-     * is diambiguated to "empty", returning 0.
+     * is disambiguated to "empty", returning 0.
      */
     static final int sub(int i, int j, int modulus) {
         if ((i -= j) < 0) i += modulus;
@@ -324,11 +325,15 @@ public class ArrayDeque<E> extends Abstr
         final int s, needed;
         if ((needed = (s = size()) + c.size() + 1 - elements.length) > 0)
             grow(needed);
-        c.forEach(this::addLast);
+        copyElements(c);
         // checkInvariants();
         return size() > s;
     }
 
+    private void copyElements(Collection<? extends E> c) {
+        c.forEach(this::addLast);
+    }
+
     /**
      * Inserts the specified element at the front of this deque.
      *
@@ -840,7 +845,7 @@ public class ArrayDeque<E> extends Abstr
             final int i, n;
             return ((n = sub(getFence(), i = cursor, es.length) >> 1) <= 0)
                 ? null
-                : new DeqSpliterator(i, cursor = add(i, n, es.length));
+                : new DeqSpliterator(i, cursor = inc(i, n, es.length));
         }
 
         public void forEachRemaining(Consumer<? super E> action) {
@@ -1235,6 +1240,7 @@ public class ArrayDeque<E> extends Abstr
 
         // Read in size and allocate array
         int size = s.readInt();
+        SharedSecrets.getJavaObjectInputStreamAccess().checkArray(s, Object[].class, size + 1);
         elements = new Object[size + 1];
         this.tail = size;