All-in-One Java Troubleshooting Tool

A co worker found this nice toy yesterday. VisualVM is a visual tool integrating several commandline JDK tools and lightweight profiling capabilities. Designed for both production and development time use, it further enhances the capability of monitoring and performance analysis for the Java SE platform.

If you want to start hands-on, have a look at the quickstartguide.

You can download VisualVM free of charge :)