Ubuntu and Sun vs. Red Hat and JBoss?

sjvn writes “In chess, there is a tactical motif called an x-ray. In it, the effect of an attacking piece is felt primarily not by the piece that’s actively being attacked, but by the piece that is shielded from the direct attack by the attacked piece. In the release of Ubuntu 7.04, with its optional Sun Java application server stack, the actively attacked piece is Red Hat Enterprise Linux, but JBoss is the real target.”