I have always found that the Sun, now Oracle, version of Java is needed for some of the Java programs that I use in Ubuntu. For 12.04 LTS, there is a ppa to install Oracle Java 7 JDK, described here. First, Oracle requires the acceptance of their license:
echo oracle-java7-installer shared/accepted-oracle-license-v1-1 select true | sudo /usr/bin/debconf-set-selections
Note: I had to modify the above command, resulting in the above form, for this to work (see ‘update’ section in above link for original).
Next, install from the ppa:
sudo add-apt-repository ppa:webupd8team/java sudo apt-get update sudo apt-get install oracle-java7-installer
A test of the Java version:
should return something like:
java version "1.7.0_07" Java(TM) SE Runtime Environment (build 1.7.0_07-b10) Java HotSpot(TM) 64-Bit Server VM (build 23.3-b01, mixed mode)
Finally, you can check the plugin for Firefox by typing
about:plugins in the address bar — you should see many Java-related enteries.