OK, this is probably an over-the-top geeky question to ask, but Christopher Ryan suggested it to me earlier today and I thought it would be a great topic. While ColdFusion can do almost anything, there are times when we need to resort to Java in order to do something ColdFusion can't. This can be using another JAR for a feature not implement by ColdFusion, or perhaps just relying on createObject to make an instance of a built-in Java object. So let me ask - which Java class have you found to be the most useful? For me it is StringBuffer. I've only had to use it a few times, but it was incredibly helpful in cases where I was creating a large string on the fly. (Like my toXML CFC.)