在Sun Java 5中的正在运行的应用程序上使用hprof

We have an enterprise java application(ear - few ejb's and a webapp) deployed on to weblogic 10 and using Sun java 5. The response time , CPU and memory usage is fine under few users of load but if we increase the concurrent users to >100 we see huge CPU spikes after some time (for eg:- load test with 100 users, the CPU goes to high after more than 30 minutes of test). We wanted to use hprof to profile the app and collect the statistics, but wanted to do it only when CPU is high i.e after 3o minutes of the test, is there a way to do it?We have an enterprise java application(ear - fe