CEDET could be replacement, although sometimes very slow, and requires customization for complex projects. I made it working with Java as well, but for last 2 years, I didn't have a chance to contribute anymore, and my fork with better Java support is outdated...

I wrote an article that should be introduction to CEDET: http://alexott.net/en/writings/emacs-devenv/EmacsCedet.html - maybe it will be useful