今天需要用到sun的jdk，但找了半天就是找不到，只有openjdk，后来才知道，是10.04中弄走了sun-java6-jdk，官方的release notes 中看
到如下一段：
Sun Java moved to the Partner repository
For Ubuntu 10.04 LTS, the sun-java6 packages have been dropped from the Multiverse section of the Ubuntu archive. It is recommended that you use openjdk-6 instead.
If you can not switch from the proprietary Sun JDK/JRE to OpenJDK, you can install sun-java6 packages from the Canonical Partner Repository. You can configure your system to use this repository via command-line:
add-apt-repository "deb http://archive.canonical.com/ lucid partner"
于是，添加上面的源后再
sudo apt-get update
sudo apt-get install sun-java6-jdk
我用的是校园网，后来加了网通的代理后速度就非常快了。