How to install Java 1.6 on Ubuntu – Ubuntu and Linux
A practical guide for installing Sun JRE 6 on an Ubuntu system, using Java as default interface for Firefox and other programs that require it.
The first step is the installation of Sun JRE 6, by typing the following command from the command line:
sudo apt-get install sun-java6-jre sun-java6-plugin sun-java6-fonts
Then, we have to choose Sun JRE 6 as default Java interface, through the command:
sudo update-java-alternatives - set java-6-sun
You can check whether Java plugins work correctly, by visiting the about: plugins page of Firefox.