Installing Java 1.4.2 would not work, and complained that I needed to install Java 1.4.1 first. Well, I had installed 1.4.1 and I tried a bunch of the solutions floating around (re-installing Apple's java.pkg, and several on this site) and nothing worked.
This is the trick that helped me install Java 1.4.2 with no errors from software update. I searched for and wide for this information so I thought I'd share it; it's adapted from a versiontracker comment.
Apple's Solution to 1.4.2 update over 1.4.1 problem ... AppleCare's advice is to find the directory QuickTimeJavaUpdate.pkg in /Library/Receipts/ and delete it. Java 1.4.2 will now update. It worked for me on two computers that suffered from this bug.
Mac OS X Hints
http://hints.macworld.com/article.php?story=2004070612462167