Java's been broken on Hardy Heron for a while, but I just upgraded to Alpha 5 and found out for myself :-(
The symptoms of the bug are a crash with an error message that contains:
xcb_xlib_unlock: Assertion `c->xlib.lock' failed.
At Dave Shucks blog, I found a patch that works:
for f in `find /opt -name "$LIB_TO_PATCH"`
echo "Patching library $f"
sudo sed -i 's/...