The openJDK BOF was interesting. It was getting into some pretty low level discussion on building and modifying the JDK, so it was a little out of my area of focus. I did pick up a few interesting things.
The Open JDK has only 4 or 5 libraries that are different from the commercial JDK. They mainly revolve around font rendering stuff. Sounds like it would be pretty easy to open source the whole JDK, but how would they make any money out of that. The question I had, but never got a chance to ask was, how do they actually make any money out of the commercial Sun/Oracle JDK? I felt a bit stupid asking that question so I kept my mouth shut.