Here is the quick guide how to do it. Of course you are able to run JDK installer and by the normal way extract the content and copy JDK somewhere but ! What to do if you want to have the JDK as system default and you do not want to create symbolic links manually ? For those people is this guide

You have to do this:

1. Download the JDK which you want from http://java.sun.com
2. You need these packages: java-package, fakeroot (install them -> apt-get install java-package fakeroot
3. Now we make a debian package from the JDK installation package by running this -> fakeroot make-jpkg jdk-1_5_0_04-linux-i586.bin (of cource you are able to do this with any jdk package)
4. Now we install the created debian package -> dpkg -i sun-j2re1.5_1.5.0+update04_i386.deb (you have to be a root to do this)
5. Now you have your choosen jdk installed as a system default. Relogin now.
6. Check the functionality -> java -version

Actually this procedure is able to apply also on the JRE )