--- old/src/share/classes/java/lang/StringBuffer.java 2013-05-20 01:31:51.535277882 -0400 +++ new/src/share/classes/java/lang/StringBuffer.java 2013-05-20 01:31:50.323209866 -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; }