Java5：
早在ubuntu 9.10中，ubuntu就已经去除了对sun-java5-jdk的支持，但是为了进行android的开发，又必须安装sun-java5-jdk。那么在享受ubuntu 10.04好处的同时，如何来进行sun-java5-jdk的安装那。经过多次的摸索，下面是一个方案：
1.编辑/etc/apt/sources.list文件，将安装源更改为ubuntu 9.04的安装源为：
deb http://archive.ubuntu.com/ubuntu/ jaunty main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ jaunty-security main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ jaunty-updates main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ jaunty-proposed main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ jaunty-backports main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ jaunty main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ jaunty-security main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ jaunty-updates main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ jaunty-proposed main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ jaunty-backports main restricted universe multiverse
2.安装java5,apt-get install sun-java5-jdk.
4.更改默认jdk的方法如下：
update-alternatives --config java
显示如下，然后键入java-1.5.0-sun的编号：
有 2 个选项可用于替换项 java (提供 /usr/bin/java)。
Java6：
ubuntu 10.04
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"
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于是：
$ sudo add-apt-repository "deb http://archive.canonical.com/ lucid partner"
$ sudo apt-get update
$ sudo apt-get install sun-java6-jdk