Here's a great tool named Eclim which brings Eclipse to vim and there's an emacs port as well. I've tested for both vim and emacs and I think vim version is better than the emacs version. Emacs version needs work. I'm jealous.

Emacs Setup

• Follow these instructions to install eclim.
• Download emacs plugin from here.
• Move downloaded emacs plugin to your .emacs.d/ Write the following to your .emacs;

(add-to-list 'load-path (expand-file-name "~/.emacs.d/eclim/vendor"))
(require 'eclim)
(setq eclim-auto-save t)
(global-eclim-mode)

Whenever you need to do Java development, first open a console and run the eclimd and then open emacs.