Javolution - Real-Time Java and Fastutil

Boost your application performance (in particular when using collections) with the Javolution API and the Fastutil API.

JAMon to monitor performance of Java programs

I discovered a nice open source monitoring API called JAMon, which aggregates the monitoring results and performs the calculation in memory. It claims to do this in a very fast way, so you can use the tool even in production environment.

It comes with a very handy and useful web application for viewing and querying the statistics.

Combined with AspectJ anyone is able to insert performance monitoring code into an existing application without touching the existing code.