Unfortunately, Java is owned by Sun Microsystems, and they do not allow it to be redistributed without special permission. So the chances are that your Linux distribution does not have Java installed. Also, Sun have made it difficult to download directly, so I can't just give you a link straight to the package. Heres what you need to do.
Goto
http://java.sun.com/j2se/1.4.2/download.html
Part way down the page, you will see the heading ' J2SE v 1.4.2_11 JRE includes the JVM technology' with a link 'Download J2SE JRE' underneath it. Click on that link.
On the next page, tick the 'Accept' radio button for the license agreement, and then download the ' self-extracting file' version from the 'Linux Platform - Java(TM) 2 Runtime Environment, Standard Edition 1.4.2_11' section of the page.
Once you have that on your linux system, login via ssh, or start a shell prompt if you are using a desktop version of linux. Then follow the instructions here
http://java.sun.com/j2se/1.4.2/install-linux.html You want the self extracting versions install instructions.
Once you manage to download everything, the install is fairly straight forward.
HTH,
Coop