JavaLobby just put online my article about JVMPI. JVMPI stands for Java Virtual Machin Profiling Interface, a really cool technology you can use with Sun's JDK to write your own JVM agents. Basically, an agent listens for events fired by the VM and use them to check the status of the VM. The well known hprof profiling tool is a JVMPI agent. Check it out!