Go directly to here if you think you know all the dark corners of the Java language and APIs. It’s a really worthwhile Google TechTalk. You will come away thinking that you had better set up automated FindBugs analysis of your code!
If you’re interested in the Scala programming language then this article will come in handy. I learned a couple of things. In particular, I didn’t realise that you could instantiate an object with a trait (effectively changing the trait from the one specified in the class definition). Very interested in how that is implemented.