I've tried many times to get jre-1.3.1 running on the 6000 with no succes. I think the problem is related to some odd fonts or libraries for fonts. Anyway, it seems impossible to launch it. In my humble opinion, the problem is not related with the 6000 specificaly. It seems like the version, based on the horrible C compiler from RedHat, 2.96, needs the old "libstdc++" not used anymore. What is almost incredible is that SUN continues to compile their last JDK's based on RedHat, instead of the free GNU serious compilers.!!!
An alternative to your problem is to use the complete jdk-118 plus the almost complete Swing that you can download for free from the Zaurus Software site. I have a couple of shots in the web-page corresponding to Debian over Xqt where you can see an example of a quite sofisticated software.