I finally get where class libraries get installed under MacOS X... after finding that technote, it all makes sense.

You go to /Library/Java which has a symbolic link inside of it (some pepole call them aliases, others shortcuts) to the home directory of the current Java installation, which happens to be 1.3 on MacOS X 10.1.5.

Maybe I'll get that Jaguar upgrade I've been dreaming of. Don't know if 1.4 comes with it or not.