Ubuntu下载安装Oracle Java JDK 6/7/8

参考自：http://linuxg.net/how-to-install-oracle-java-jdk-678-on-ubuntu-13-04-12-10-12-04/

$ sudo apt-get install software-properties-common

Add the PPA:

$ sudo add-apt-repository ppa:webupd8team/java

$ sudo apt-get update

Install Java 8:

$ sudo apt-get install oracle-java8-installer

Install Java 7:

$ sudo apt-get install oracle-java7-installer

Install Java 6:

$ sudo apt-get install oracle-java6-installer

 Then change:

sudo update-alternatives --config java