First, there is no Java plugin for Mozilla in the latest IBM's JDK on Powerpc, there is now gcjwebplugin, running on many architectures! For several weeks now IBM's JDK (1.4.1 and 1.4.2) does not run at all on my Debian/sid powerpc. I cannot run ant, tomcat, nothing. I got a javacore_blablabla file with a lot of debug information. SableVM, gic/gcj, Kaffe and JamVM already run Ant (nearly) without problem.
Update: a hack with an envvar is necessary: 'export JITC_PROCESSOR_TYPE=6'
The next peace I need is Tomcat4. It's now done (screenshot). The work around was to remove the xmlParserAPIs.jar and xercesImpl.jar from the tomcat4 directory (/usr/share/tomcat4/common/lib) and replace them with a symlink to gnujaxp.jar (in /usr/share/java). And nearly everything was fine (Struts does not seem to work, but all the servlet examples did work, and every JSP examples did work except two: one because the mail api was not in the tomcat classpath and the other because of an exception in org.apache.jasper.servlet.JspServlet.service... I think it was the same exception that occured with Struts.
JDEE for Emacs seems very bounded to proprietary JDK's but I'd like to investigate a little more to have it working with free JDK's as I use it for sometimes now and I'm very happy with it. Another great environment that would be cool to run is Eclipse...
Long life to Free Java! ;-)