添加源
sudo vim /etc/apt/sources.list.d/java-8-debian.list
添加
deb http://ppa.launchpad.net/webupd8team/java/ubuntu trusty main
deb-src http://ppa.launchpad.net/webupd8team/java/ubuntu trusty main
添加GPG key
sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys EEA14886
安装java8
sudo apt-get update
$ sudo apt-get install oracle-java8-installer
验证java版本
java -version
设置java8为默认
sudo apt-get install oracle-java8-set-default