Install Java Firefox Chrome Ubuntu jre openjdk icedtea

Install openjdk using the following command from your terminal

sudo apt-get install openjdk-7-jre

Install Java for browser – firefox/chrome..
For running applets in your web browsers such as Mozilla Firefox or Google Chrome, you need to install icedtea plugin. Execute the following command from your terminal

sudo apt-get install icedtea6-plugin

from http://www.ubuntugeek.com/install-jre-on-ubuntu-11-10-oneiric.html