In the new announced Ubuntu 10.10, the sun-java6-jdk packages have been removed from the Multiverse section of the Ubuntu archive. So you cannot install it using the command sudo apt-get install sun-java6-jdk directly!!!
To install sun-java6-jdk on Ubuntu 10.10, type the commands below in Terminal:
$sudo add-apt-repository "deb http://archive.canonical.com/ lucid partner"
$sudo apt-get update
sudo apt-get install sun-java6-jdk
and follow the steps.
