http://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html

    vi /etc/profile

    1. #Java Env
    2. export JAVA_HOME=/usr/jdk1.8.0_121
    3. export CLASSPATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar
    4. export PATH=$PATH:$JAVA_HOME/bin

    source /etc/profile

    1. java -version
    2. java version "1.8.0_121"
    3. Java(TM) SE Runtime Environment (build 1.8.0_121-b13)
    4. Java HotSpot(TM) 64-Bit Server VM (build 25.121-b13, mixed mode)