Using VisualVM, BTrace & Good Old Web Search

The story starts with my pattern of being off the grid half of each day. This really lets me appreciate a good battery and, while my Mac battery is pretty decent, I can literally feel it drain while doing hard Java work with NetBeans IDE, Maven, and big recompiles.

Now, while battery depletion under heavy load is perfectly normal, it does force you to keep a keen eye on CPU usage in the OSX Activity Monitor. That's how I noticed that while idle, NetBeans IDE was taking about 16% of my CPU... doing nothing really.

The first thing I wanted to know was what was going on in there? So I took VisualVM, connected it to the NetBeans IDE instance, and forced a Thread Dump:

This basically is a list of stack traces for all the threads, so that you can see the application's current state of execution. In my case, I probably didn't press the button at the right time, since I caught the threads all in a WAITING state, meaning that not much CPU should have been used: 

Well, since the thread dump is just a quick snapshot, it was clear that I wasn't going to get a good view of what was consuming CPU, so I went to the heavy weight option: CPU Profiling.