Bugs in free java programs and libraries -- run for your life! The SableVM Project has just released a snapshot of SableVM with JVMDI/JDWP support. You can take a look at Debugging in Eclipse with SableVM in action while downloading the snapshot.
The Quick-start instructions included in the announcement should get you going within minutes. There is also a longer version available, containing the SableVM and Eclipse Debugging Troubleshooting FAQ and other interesting notes.
Many thanks go to Nizar Ahmouda who has been working on the implementation of JVMDI and JDWP since many months. We all hope that this completly unique among Free Java Virtual Machines functionality will serve well the Free Java Community, especially the GNU Classpath developers.
There is finally a nice page that includes all necessary informations on how to run GNU Classpath CVS directly with SableVM. There's also some discussion with more experienced GNU Classpath developers about making the SableVM and GNU Classpath duo even easier to use.
In case you were wondering... SableVM's class library is over 99% GNU Classpath, the differences are pretty much only in the core, JVM-specific classes and we merge GNU Classpath CVS regularly. Still, for the people working directly with GNU Classpath CVS it might be more convenient to build one class library and test it with many JVMs.
Not to mention that this way one can actually debug GNU Classpath directly... with Eclipse and SableVM of course!