diff -r 8be4a665d07e -r 9a1076231db7 jdk/src/share/classes/java/util/Calendar.java
--- a/jdk/src/share/classes/java/util/Calendar.java	Tue Jan 24 15:13:27 2012 -0500
+++ b/jdk/src/share/classes/java/util/Calendar.java	Thu Jan 26 17:06:47 2012 +0900
@@ -2705,7 +2705,7 @@
      * removed from the serialization stream; this will probably happen in the
      * near future.
      */
-    private void writeObject(ObjectOutputStream stream)
+    private synchronized void writeObject(ObjectOutputStream stream)
          throws IOException
     {
         // Try to compute the time correctly, for the future (stream