I have Java working perfectly on my SL-6000. I have jdk-1.1.8 but also Jeode and apart from that, a package with Swing.
I have installed everything without any use of ipk packages. Just downloading the JVM for Debian (I use Debian under Xqt). For Jeode, I don't care at all about licenses and other similar stories. I received my first 5500 with Jeode so I payed for everything, hardware and software. As I don't obtain any profit for my programs I don't feel any need to do any other way.
Coming back to Java, it should work exactly the same on the C-3000. In fact, my son has a 860 and the JDK and Swing work perfectly. I don't remember about Jeode.
Don't forget that Jeode is only useful if you use Qtopia. If you change to pdaXrom, it is of no use.
Finally, if someone wnat to see some nice snapshots of Java-programs running on Zaurus, I have put some on the page http://w3.mecanica.upm.es/~smuelas/debianxqt.html
If some one continue to be interested in having Java installed and working on his Zaurus, please contact me at firstname.lastname@example.org and I will help as much as possible.