Ubuntu install sun jdk6

at first i tried choosing all selections under the first tabs of software source, but sun-java6-jdk still cannot be found, then i tried the following commands in terminal, it WORKS!!!.

sudo apt-get install python-software-properties

sudo add-apt-repository ppa:sun-java-community-team/sun-java6

sudo apt-get update

sudo apt-get install sun-java6-jdk