FYI, YourKit, the Profiler I've been using, has free open source
licenses for committers. Likewise IntelliJ does the same thing. I've
been using YourKit for a while now on Mahout and it has been pretty
helpful in finding the bottlenecks. Plus, it integrates nicely w/
IntelliJ and Eclipse.
And, no, I'm not paid by them or any in way, shape or form, affiliated
with them. Just thought others might benefit.