Little somethin' for Android devs embarking on their first real project: If your application crashes and you can't seem to figure out why, start by ensuring that every statement (save the ones that import libraries) are in methods.
When I was building my first Android app, I spent an entire week trying to switch Activities without crashing; even enlisting the help of a friend. What he failed to notice was that the statements that collected data from the previous Activity were outside of a method, which led to a fatal error. I'd imagine this is much less of a problem in Java programs with a dedicated main method.