Java VisualVM Screencast
Java VisualVM is a new JDK tool added since JDK 6 Update 7 (<JDK>/bin/jvisualvm). It provides a nice graphical user interface for monitoring and troubleshooting Java applications and integrates several troubleshooting features introduced in JDK 5 and 6 as command-line utilities into this single GUI tool.
I like their screencast that shows VisualVM in action. It should help you get started. I also embed it here for your convenience:
See also the Java VisualVM User Guide:
VisualVM project page:
Let the VisualVM team know what you think and any feature you'd like to see.