This is not a Java game-specific topic, but I found use for it when I wanted my users to record videos in the game without using the JMF (which I found to be very non-intuitive):
http://blog.hslu.ch/rawcoder/2008/08/12/writing-avi-videos-using-pure-java/ (http://blog.hslu.ch/rawcoder/2008/08/12/writing-avi-videos-using-pure-java/)
I also consider this method to be a replacement for Fraps (without sound yet though) and other video capture software that you don't get full control over.