Comment 8 for bug 198093

That PPA doesn't seem to contain a plugin for Firefox.

I've installed the openjdk-7-jdk package and the plugin definitely seems to be missing. I don't see any other packages starting with 'openjdk' that look like they might provide that. Trying to switch my alternatives to use openjdk-7 gives this error:

$ sudo update-java-alternatives -s java-7-openjdk
update-java-alternatives: plugin alternative does not exist: /usr/lib/jvm/java-7-openjdk/jre/lib/i386/IcedTeaPlugin.so