1. 新增ppa

$sudo add-apt-repository ppa:webupd8team/Java (ORACLE)

$sudo add-apt-repository ppa:openjdk-r/ppa (OpenJDK)

2. 安裝 openjdk-8-jdk

$sudo apt-get update

$sudo apt-get install openjdk-8-jdk

3. 只對特定使用者user採用java 8

$sudo update-alternatives --config java  

選擇非1.8

$sudo update-alternatives --config javac 

選擇非1.8

[email protected]~$ vim .bashrc

新增:

#export JAVA_HOME=/usr/lib/jvm/java-8-oracle   (ORACLE)

export JAVA_HOME=/usr/lib/jvm/java-8-openjdk-amd64   (OpenJDK)
export JRE_HOME=${JAVA_HOME}/jre
export CLASSPATH=.:${JAVA_HOME}/lib:${JRE_HOME}/lib
export PATH=${JAVA_HOME}/bin:$PATH

[email protected]~$ source .bashrc

[email protected]~$ java -version

openjdk version "1.8.0_111"
OpenJDK Runtime Environment (build 1.8.0_111-8u111-b14-3~14.04.1-b14)
OpenJDK 64-Bit Server VM (build 25.111-b14, mixed mode)