I'm working on a large XPages project at the moment which is almost exclusively Java. In fact one of the key deliverables for the project is that we are not allowed to use SSJS unless we can specifically justify every single line!
One of the other key deliverables is a useful Javadoc package be produced at the end of the development phase. It's one of those things which sounds easy enough, but I find that time after time I forget to write the Javadoc comment for a new function that I create, my mind is in coding mode and I move onto the next thing. Going back and doing documentation is very very boring (why do you think I'm displacing and writing this blog entry!) so I had a quick dig into the huge Preferences window in Eclipse (well Domino Designer in this case, but it's the same thing).
Guess what I found under Preferences -> Java -> Compiler -> Javadoc -> Missing Javadoc comments? I can choose to generate a warning or an error when there are missing comments, this makes it much easier to keep on top of things as I go along.
Now I have no choice but to get back to my documentation!