--- a/src/java.base/share/classes/java/util/ArrayDeque.java	Tue Jul 10 11:13:33 2018 -0400
+++ b/src/java.base/share/classes/java/util/ArrayDeque.java	Tue Jul 10 10:24:08 2018 -0700
@@ -180,7 +180,7 @@
      * sufficient to hold 16 elements.
      */
     public ArrayDeque() {
-        elements = new Object[16];
+        elements = new Object[16 + 1];
     }
 
     /**