I just created a new project entry for the GNU Classpath Extensions, supporting Free Java interfaces and implementations of javax.* packages. The JAXP software there is nearly ready for a release, one of these days I hope to put together a source distribution and binary release.
As of GCC 3.0, the GCJ support is beginning to get interesting enough to start thinking of large systems of GPL'd (or LGPL'd) Free Java, although it's not quite up to the everything that, say, JDK 1.1 is ... there are hard problems, and Sun's business strategies are no help.