Am 19.02.2013 06:27, schrieb Mike Duigou: > http://cr.openjdk.java.net/~mduigou/JDK-7197183/0/ I think, you should add || (s instanceof AbstractStringBuilder) as third in else if ((s instanceof StringBuilder) || (s instanceof StringBuffer)) { , as someone could use his own subclass of AbstractStringBuilder. -Ulf