Thank you for the suggestion.
I read about and got it yesterday but so far it looks like a more complicated setup for me.
Keep in mind that I don't have the experience in the internals of Java that most of you have.

Certainly too much work to insert 3-4 bytes in a method (:

I'd still be curious why the Javassist sample doesn't work for me.
Would a 32-bit JDK behave differently? I couldn't find any mention which JDK version Javassist needs.