JNode and Mauve project
I am now also working for the Mauve project.
Mauve is a project aiming at testing the core Java libraries implementations, like GNU Classpath (that JNode is using).
Mauve not only tests the core classes but also the VM. By working on that, we help reporting bugs in Classpath but also in JNode VM... all that in order to be compatible with JLS (Java Language Specifications).
In the near future, I hope to be able to run them under JNode.