--- a/jdk/src/share/classes/java/util/EnumMap.java	Mon Jan 30 11:44:45 2012 +0000
+++ b/jdk/src/share/classes/java/util/EnumMap.java	Tue Jan 10 00:07:13 2012 +0000
@@ -106,7 +106,15 @@
     /**
      * Distinguished non-null value for representing null values.
      */
-    private static final Object NULL = new Integer(0);
+    private static final Object NULL = new Object() {
+        public int hashCode() {
+            return 0;
+        }
+
+        public String toString() {
+            return "java.util.EnumMap.NULL";
+        }
+    };
 
     private Object maskNull(Object value) {
         return (value == null ? NULL : value);