Had a really strange problem with JSF before the weekend. A command button was supposed to save the form, but instead, the page would just rerender, as if it failed validation. It turned out to be just an ordinary null pointer exception, but it took some time to realize that because no stack trace showed up, and the h:message box was empty.

I guess sooner or later someone will search for this problem, so here is the post I found that solved it: http://forums.sun.com/thread.jspa?messageID=3263230  . I had to change it a little to get it to work, but I guess those changes has disappeared since then. (Of course I didn't submit those changes, as they were just for debugging.)

(Yes, someone is going to search for what you just found out, so you better start blogging now. Big thanks goes to everything is Broken for sharing how to get the Trust Flat Scan USB 19200 working under linux.)