vim QuickFix is a nice feature that figures out how you screwed up your code by looking at compiler errors. It repositions your cursor over the first offending line and will show you the other errors on demand.
By default, it's set up for C/C++, but it's easy enough to set up for Java if you're using Ant. Set your 'makeprg' to ant without logging adornments:
:set makeprg=ant\ -emacs
And make a mistake in your Java code. Run ':make', and vim will background while ant runs. When you return to vim, your cursor should be over the error and you can run ':cl' to see the other errors in the compilation. Cool.
You'll need to make sure that your current working directory contains the build.xml file; I do this by using vimproject.