Install the Java components which are in java-6-openjdk or contained within ubuntu-restricted-extras:

sudo apt-get install java-6-openjdk

# I used this one because it gives a heap of oft needed codecs
sudo apt-get install ubuntu-restricted-extras

To test goto:
http://www.java.com/en/download/testjava.jsp

You should see:

I think this uses java-6-openjdk to give the java plugin functionality. By the time you resolve all the symlinks the plugin is located /usr/lib/jvm/java-6-openjdk/jre/lib/i386/IcedTeaPlugin.so