Install JDK&JRE in ubuntu by apt-get

I am a new bird in Linux & Ubuntu, and I think the first thing to use an Android related work is to install JAVA on Ubuntu. And this easy job takes two days for me so I must have a record because I cannot have any useful search result on Google.

Stepwise :
1. find the package link on Ubuntu official website.
http://packages.ubuntu.com/hardy/all/sun-java6-jre/download
2. Add the upon link to etc\apt\sources.list
3. Open `terminal`, type `apt-get install sun-java6-jre`.
4. Type `apt-get install sun-java6-jdk`.

P.S.
JDK and JRE have the same source link.

Actually, it`s ok to install just JDK6 if we only want to run a Android CTS or Android Monkey Tool, but it`s need a JRE if you want to run a Android project which like AndroidScreenCast. I think this kind of Android test tool is very easy to use.

Maybe I am too new to Ubuntu, no search result tell me where to find a package link, haha.