Quote (m0hawk @ Apr 22 2013 07:20am)
For the sake of completeness, you should use StringBuffer (http://docs.oracle.com/javase/1.4.2/docs/api/java/lang/StringBuffer.html) when doing operations such as replace, concatenation etc on strings.
StringBuilder should be used over StringBuffer 99% of the time because StringBuilder isn't synchronized and therefore has better performance.