install jdk on Ubuntu 10.10

$ sudo add-apt-repository "deb http://archive.canonical.com/ lucid partner"
$ sudo apt-get update
$ sudo apt-get install sun-java6-jdk   
or {Depending upon what you need)
$ sudo apt-get install sun-java6-jre




source : http://www.botskool.com/forum/computer-programming/linuxunix/install-sun-java-6-ubuntu-1004-jdk-jre