Most, but not every minute of my last few months have been filled with OpenSolaris. I also attended a meeting in November where the GNUClasspath folks were trying to understand how to gain access to the J2SE TCKs so they can check their work for compatibility. This is very exciting. Now today a friend has pointed out "this". At the same time, our friends in Brazil have finally achieved full funding for the "javali" project.
AFAIKS, this is all goodness. Compatible Open Source J2SE was a foregone conclusion back in March of 2002 when the rules of the JCP changed to support compatible open source re-implementation of JCP specifications. As happened last year with J2EE, there will probably be multiple compatible open source re-implementations. The thing to watch for with IBM or anyone starting such a project is transparent open source licensing and process and full support for compatibility.