;; start auto-completion with emacs
(require 'auto-complete)
;; do default config for auto-completion
(require 'auto-complete-config)
(ac-config-default)
;; add the emacs-eclim source
(require 'ac-emacs-eclim-source)
(ac-emacs-eclim-config)
You need to install the ac-emacs-eclim package from Melpa: