64 bit Java on Mac OS X

I completely switched my development platform to PowerPC G5 and got curious of whether Java on Mac OS X supports 64-bit mode. The answer is, there's no explicit option for the mode, but certainly some benefit explained at http://developers.sun.com/learning/javaoneonline/2004/javatechdesktop/TS... . Please correct me if I'm wrong about it and honestly, I wish some day we can see the option on Mac.