I just upgraded to Java 1.4.1, and all seems great. jEdit is much more responsive, and the SCROLL WHEEL WORKS! YAY! It's SOOO much faster than 1.3.1 was, and this is without the hardware accelerated SWING (I've got a pokey Powerbook G4/400, and the video card isn't up to snuff for that).
It's interesting that although 1.4.1 was rumoured to be a from-the-ground rebuild in Cocoa, the Services menu still doesn't seem to work from within java apps. Hrm...
The only drawback I've come across so far is a minor nitpicky thing. ProjectBuilder insisted on rebuilding its class index when I opened CAREO in it. Took almost 30 minutes, and indexed SWING et al. CPU was running at 100% the whole time, too. I just KNOW that when I open UCRepositoryCore, it will insist on re-indexing the entire java world again. Doh.
UPDATE: Yup. It's re-indexing the entire known Java Universe... Oh, well...