Ubuntu 10.04 LTS 安装Java 6方法：
$ sudo add-apt-repository "deb http://archive.canonical.com/ lucid partner"
$ sudo apt-get update
$ sudo apt-get install sun-java6-jdk
注意事项：
Ubuntu 10.04 LTS 安装 sun-java6-jdk ，出现错误。
Reading package lists... Done
Building dependency tree
Reading state information... Done
Package sun-java6-jdk is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source
E: Package sun-java6-jdk has no installation candidate
说是Ubuntu 10.04已经去掉 sun-java6-jdk 和 sun-java6-jre的软件包
解决方法：
1. sudo gedit
2. 打开 /etc/apt/sources.list
3. 添加一行
deb http://us.archive.ubuntu.com/ubuntu/ hardy multiverse
4. 保存关闭gedit
5. 运行 sudo apt-get update
6.再运行sudo apt-get install sun-java6-jdk