http://ubuntuforums.org/showthread.php?t=193018
sudo gedit /etc/apt/sources.list
## Uncomment the following two lines to fetch updated software from the network
deb http://archive.ubuntu.com/ubuntu dapper main restricted
deb-src http://archive.ubuntu.com/ubuntu dapper main restricted
## Uncomment the following two lines to fetch major bug fix updates produced
## after the final release of the distribution.
deb http://archive.ubuntu.com/ubuntu dapper-updates main restricted
deb-src http://archive.ubuntu.com/ubuntu dapper-updates main restricted
## Uncomment the following two lines to add software from the 'universe'
## repository.
## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team, and may not be under a free licence. Please satisfy yourself as to
## your rights to use the software. Also, please note that software in
## universe WILL NOT receive any review or updates from the Ubuntu security
## team.
deb http://archive.ubuntu.com/ubuntu dapper universe
deb-src http://archive.ubuntu.com/ubuntu dapper universe
deb http://security.ubuntu.com/ubuntu dapper-security main restricted
deb-src http://security.ubuntu.com/ubuntu dapper-security main restricted
deb http://security.ubuntu.com/ubuntu dapper-security universe
deb-src http://security.ubuntu.com/ubuntu dapper-security universe
deb http://archive.ubuntu.com/ubuntu dapper multiverse
deb-src http://archive.ubuntu.com/ubuntu dapper multiverse
deb http://archive.ubuntu.com/ubuntu dapper-backports main restricted universe multiverse
Then run sudo aptitude update
Then run sudo apt-get install sun-jave5-jre
