I tried vi integration in Eclipse a long time ago, gave up because the integration was crappy. I don't remember what I used. Anyway, I just checked again and found Eclim which has great features. It doesn't hurt that it's free + open source, unlike viPlugin which costs 15 Euros.

Update: I finally managed to get Eclim sort of running on my Mac. After wasting time to discover that the Eclim installer didn't recognize Mac Vim, I downloaded Vim source for unix and ran configure + make + make install, then the Eclim installer let me proceed. So I started eclimd but the first test failed, I cannot run :PingEclim. The docs say I should go to the forums for help. You've got to be kidding! I've already wasted enough time to declare Eclim a lame, half-baked solution, and the install docs are to post on forums and wait for who-knows-how-long? ...Deleting Eclim right now...