Visualvm is able to measure application performance (profiler) and monitor system resources.
It’s really a nice tool if you need to monitor your tomcat and get some informations about threads, memory usage, cpu load, loaded classes, etc.
I’d say this application is fundamental to watch over your tomcat …
- Screencast: http://blip.tv/kg/introduction-to-java-visualvm-1591181
- Eclipse launcher: http://visualvm.java.net/eclipse-launcher.html