--- a/jdk/src/share/classes/java/util/EnumMap.java	Thu Jun 07 10:31:48 2012 +0100
+++ b/jdk/src/share/classes/java/util/EnumMap.java	Thu Jun 07 12:31:45 2012 +0100
@@ -730,6 +730,7 @@
             throw new AssertionError();
         }
         result.vals = result.vals.clone();
+        result.entrySet = null;
         return result;
     }