I wouldn't bother with Java 1.1 at this point.
The Java you get from Sun will require you to have the version of the C
runtime library that it was compiled for, which is older than what Woody
or Sid use at this point. (I don't recall offhand what libc Potato
uses.) It's available in the oldlibs section, however, so you can get
the Sun packages to work without too much trouble. I think
libstdc++2.9-glibc2.1 is the one you need. Of course, Sun doesn't offer
.debs, so you'll be working outside the Debian package system; annoying,
but doable.
Blackdown's Debian Potato or Woody packages should install and work
perfectly with no extra libraries required. This is probably the best
way to go if you are willing to settle for Java 1.3, which is probably
adequate for now. Blackdown doesn't have Java 1.4 available yet, though
apparently they are working on it.
I need Java 1.4 for the development work I'm doing, so I use Sun's JDK.
I'll consider replacing it with a proper .deb when Blackdown has one.
Craig