I installed the latest release of Ubuntu - 7.04 on my home computer. I am quite happy with it, however I am a bit disappointed that Sun's Java is still not available by default. The default Java is GCJ, which unfortunately is not 100% Sun java compatible. So how to exchange GCJ for Sun Java?
java version "1.6.0"
Java(TM) SE Runtime Environment (build 1.6.0-b105)
Java HotSpot(TM) Client VM (build 1.6.0-b105, mixed mode, sharing)
I hope that Sun's Java will become default in Ubuntu soon. Not sure if there are any reasons why it should not be the default, now that it's fully open source. The experience will be much better for beginners who may run into problems with GCJ because it doesn't support all Java applications at this moment.