--- old/src/share/classes/java/util/AbstractSet.java	2013-05-06 14:43:32.178817172 -0700
+++ new/src/share/classes/java/util/AbstractSet.java	2013-05-06 14:43:31.978817163 -0700
@@ -166,6 +166,7 @@
      * @see #contains(Object)
      */
     public boolean removeAll(Collection<?> c) {
+        Objects.requireNonNull(c);
         boolean modified = false;
 
         if (size() > c.size()) {