How you install and configure java on a debian machine

If you want to install JRE:
# apt-get install sun-java5-jre

If you want to install JDK:
# apt-get install sun-java5-jdk

If you want to install Java plugin for the browser:
# apt-get install sun-java5-plugin

If you want to install Java documentation, install this package and follow the instructions:
# apt-get install sun-java5-doc

If you wan to install some fonts:
# apt-get install sun-java5-fonts

If you want to install some demos for the JDK:
# apt-get install sun-java5-demo

After you have installed everything you want, you need to make sure that Sun java is the default Java runtime environment:
# update-java-alternatives –set java-1.5.0-sun