"Tiger on Tiger", that is, the ability to run Java 1.5 (codenamed Tiger) to run on, yes, Mac OS X Tiger (10.4), was one of the features of the upcoming release. The features page actually writes that 1.4.2 would be what it will be shipping with. The Apple developer/spokesperson at the WWDC event had some really great demos of using some Java 3D library - more than once the thought of "it can't be Java on the desktop" crossed my mind.