I was unlucky to work for one of italy's regional IT office. Damm were they stingy. The project was based on jsp, xml and oracle and I had a crummy Pentium I with 2Gb HDD e 64Mb or ram and they expected me to do the work on time!
So for me the best java ide which worked fine was GEL Java IDE http://www.gexperts.com/
with code completion for both java and jsp!
Give it a try.