Comment 4 for bug 600642

The issue is that your links are pointing to libjavaplugin_oji.so, which is not supported (the OJI support was removed from FF3.6). I'm not sure what has registered it as an alternative, because it's not listed on mine.

You need to use the libnpjp2.so plugin. To fix this, run "sudo update-alternatives --config mozilla-javaplugin.so" and select the right plugin. Do this also for xulrunner-javaplugin.so and firefox-javaplugin.so, restart Firefox and you should have the sun java plugin again.

This isn't a firefox bug, but i need to figure out what we can do about this