在ubuntu10.04版本里面，sun的jdk已经不是在标准库里面，标准库的只有openJDK了，sun的jdk已经被放到partner库里面，所以如果要安装jdk，需要以下步骤：
To enable Partner Repo:
SYSTEM -> ADMINISTRATION -> SOFTWARE SOURCES -> OTHER SOFTWARE
-> ADD
deb
http://archive.canonical.com/
lucid partner
Then CLOSE window and RELOAD, then search for Sun Java
You should find Version 6.20 ..... Install