For anyone interested in Java 7, I have built OpenJDK 7 (via IcedTea) for BUG 2.0 (Angstrom, armv7, Zero VM). The binaries are available here. The binaries are not provided as Angstrom opkgs, so the installation process is manual. This is because it was built natively on a BUG, rather than using the OpenEmbedded cross compiling build system. You'll also need to install libcups2 via opkg if you want to replace the Java 6 JRE to run BUG...