Test tools that generate load against the front end of an application and then report the bumps have their usefulness. Sometimes the test surfaces a performance bottleneck. I am all for these kind of bump reports.
There a lot of monitoring tools to watch the backend of an application: Glassbox uses AOP to observe thread deadlocks, memory leaks, and slow Hibernate-based database queries, Spring compiled classes come with instrumentation for memory, threads, and object processing timing, Nagios and Hyperic feature monitoring agents, and commercial tools like dynaTrace watch for performance bumps.
TestMaker's PTTMonitor module is a gateway to Glassbox, Spring, Nagios, dynaTrace, and Hyperic statistics. PTTMonitor logs to an RDBMS and the TestMaker Results Analysis Engine uses Jasper Reports to show correlation between the backend measurements and the load test running on the front end.
No reporting tool is going to be as insightful as a good Java engineer. TestMaker with Jasper Reports is a good help to surface a performance bottleneck and get an engineer to look in the right direction for the root cause of the problem.