I was using Jetspeed 2.1.3 in a projet with a lot of hits and I had to maximize the application throughput. With a lot of profiling of the application, I found few possible optimizations to the Jetspeed code and one of them was that the BatchedStatistics class was execively synchronizing. I had the chance to use a Java 1.5 environnement and I came with a patch using java.util.concurrent api and removing synchronize blocks.
This patch was tested with jmeter and a profiler and proved to increase the server throughput. It is also in use in production environement for over a year without problems.
Since Jetspeed 2.2 now require Java 1.5, I have ported this patch created for J-2.1.3 to J-2.2. The patch could be integrated in your code and I hope this could be my first stone to the project.
Please feel free to ask questions about my implementation.