Become a Java Blackbelt

Do you know http://www.javablackbelt.com? I recently discovered this site and I like it a lot. There you can take exams about Java and related technologies like XML, Eclipse etc. While commercial sites charge you a fee for taking exams, Javablackbelt doesn't want you money. They want your contribution. So before sitting down to take an exam you need to accumulate points to "pay" for it. Points are collected by reviewing questions, contributing new questions or commenting on existing topics. Questions, edits and comments need to be accepted (see the site for details) to score. This way you get a double bonus: not only you can test your knowledge, but also you are required to crack your head what would be a good question to ask. Clearly the site doesn't aim at greenhorns (which I suspect is the group I still belong to regarding Java) since I couldn't figure out how you could contribute/benefit with only little knowledge