Gary Frost from BMC Software had a BOAF session on scripting debug tasks in JAVA. Using JAVA enabled scripting shells/APIs like BeanShell and http://groovy.codehaus.org/, he hooked into the JVM debug interface using a standard API he built and could get output on a number of events; methods starting, break point insertions, etc. Pretty funky stuff, and looks like anyone can replicate his work, though he is going to release it publicly, so keep an eye out for it.