Red Hat just made it possible to bootstrap OpenJDK using only Free Software by building on top of gcj and replacing the binary blobs with code from GNU Classpath. The result is called IcedTea. IKVM also made a GNU Classpath/OpenJDK hybrid making it possible to run parts of the OpenJDK class libraries on mono and .net. And finally the Cacao team released a
new version of Cacao that can use either GNU Classpath for a full J2SE implementation or that uses the Sun GPL J2ME libraries, including jits for lots of different architectures (alpha, arm, mips, ppc, ppc64, x86 and x86_64).