Performance has been a concern of Java programmers since version 1.02 - so naturally there are an enormous number of tools for measuring various aspects of performance. There are whole web sites and multiple books devoted to performance.
If you are looking for a recommendation you will have to describe your problem better.
Bill
Post by:autobot
Every plan is a little cooler if you have a blimp. And a tiny ad.
a bit of art, as a gift, the permaculture playing cards