Getting Java plugin to work in FireFox 3 on Ubuntu 9.04 Jaunty Jackalope
on Wednesday 27th May, 2009 Gabe speculated thusly…Ensure that you have the package sun-java6-jre installed and then run the following command from a terminal:
sudo ln -s /usr/lib/jvm/java-6-sun/jre/plugin/i386/ns7/libjavaplugin_oji.so /usr/lib/firefox-3.0.10/plugins/
You will need to restart FireFox after this and Java should be working for FireFox now.