https://tecadmin.net/install-oracle-java-8-ubuntu-via-ppa/
https://www.digitalocean.com/community/tutorials/how-to-install-java-with-apt-get-on-ubuntu-16-04
1、安装jdk
$ sudo add-apt-repository ppa:webupd8team/java $ sudo apt-get update
安装java9 sudo apt-get install oracle-java9-installer
安装java8 sudo apt-get install oracle-java8-installer
安装java7 sudo apt-get install openjdk-7-jdk
安装java6 sudo apt-get install oracle-java6-installer
选择java版本:
sudo update-alternatives --config java
2、配置环境变量
ubuntu如何指定java版本:
1、指定source
vim /.bashrc
-> source /etc/envirement
wq
sudo vim /etc/envirement
往里面加两行:
JAVA_HOME=/usr/lib/jvm/java-7-oracle
JRE_HOME=/usr/lib/jvm/java-7-oracle/jre