--- a/jdk/src/share/classes/java/lang/StringBuffer.java	Wed May 22 16:43:04 2013 -0700
+++ b/jdk/src/share/classes/java/lang/StringBuffer.java	Wed May 22 20:21:13 2013 -0400
@@ -335,10 +335,8 @@
      * @since 1.5
      */
     @Override
-    public StringBuffer append(CharSequence s) {
-        // Note, synchronization achieved via invocations of other StringBuffer methods after
-        // narrowing of s to specific type
-        // Ditto for toStringCache clearing
+    public synchronized StringBuffer append(CharSequence s) {
+        toStringCache = null;
         super.append(s);
         return this;
     }