As a Windows user, I was amused how not easy to install Java on Ubuntu Linux (10.04) nor installing Java (1.6) plugin into Firefox (3.6). It's not nearly a download-next-next-finish task. Additionally, digging into forums I found a lot outdated solutions which I tried and soon realized that they doubtlessly aren't working. Here is the one which worked for me: First, open a terminal window: Applications menu -> Accessories -> Terminal. Type the followings (you will be promted for admin password, because sudo prefix means you want to do something in the name of the super (or sytem) user): sudo add-apt-repository "deb http://archive.canonical.com/ lucid partner" sudo aptitude update sudo aptitude install sun-java6-jdk Then you have to select things with arrows and pressing enter. Then Timothy says in the forum you have to type this, but I didn't need it: sudo update-alternatives --config java Now you can check if java is installed by typing java -version .