OpenJDK 7 is supposed to be the standard reference now for all Java implementations, including Oracle’s. So Ignition should be compatible with OpenJDK 7. To be sure, we are going to start testing Ignition using OpenJDK 7, and if all goes well, it will become the standard Java package dependency for Ignition installations thru the repositories. You can still use Sun Java 6 with Ignition using 3rd-party repositories, but who knows how much longer those will last.