jvmti toolbox is a project which will help me understand how to build JVMTI agents.
New capabilities will appear soon.
It is built against a 32bit Windows jdk1.7.0_04, should be however portable to other jdk7 versions.
Further changes will show how to add interesting capabilities to the agent.
Load the agent using -agentpath, e.g.
java -agentpath:jvmti-demo.dll -jar myjar.jar