Optimizing Java?

cllajoie asks: "Every programing language has a list a mile long of optimization tips ranging from the mundane to the cryptic. I was wondering if anyone has compiled a list of these tips and tricks for Java. Some things are fairly easy, like adding final to methods so that they get inlined by the compiler, but what other deeper, darker secrets does Java have for making code faster and what are their implications on code size and memory usage? For example, if I had an accessor method is it better to use the this "pointer" in the return statement or not, or does it make any difference at all in performance? I mean lets face it, Java isn't blazingly fast to begin with so every little bit in the area helps."