change_jdk

if [ x$1 == x ]; then
    echo default jdk1.7
    exit 0
fi

if [ x$1 == x1.6 ]; then
    echo change jdk to 1.6
    export JAVA_HOME=/usr/lib/jvm/jdk1.6.0_37
    export JRE_HOME=$JAVA_HOME/jre
    export CLASSPATH=.:$JAVA_HOME/lib:$JRE_HOME/lib:$CLASSPATH
    export PATH=$JAVA_HOME/bin:$JRE_HOME/bin:$PATH
    java -version
fi

if [ x$1 == x1.7 ]; then
    echo change jdk to 1.7
    export JAVA_HOME=/usr/lib/jvm/java-7-openjdk-amd64
    export JRE_HOME=$JAVA_HOME/jre
    export CLASSPATH=.:$JAVA_HOME/lib:$JRE_HOME/lib:$CLASSPATH
    export PATH=$JAVA_HOME/bin:$JRE_HOME/bin:$PATH
    java -version
fi

if [ x$1 == x1.8 ]; then
    echo change jdk to 1.8
    export JAVA_HOME=/usr/lib/jvm/java-8-openjdk-amd64
    export JRE_HOME=$JAVA_HOME/jre
    export CLASSPATH=.:$JAVA_HOME/lib:$JRE_HOME/lib:$CLASSPATH
    export PATH=$JAVA_HOME/bin:$JRE_HOME/bin:$PATH
    java -version
fi

gatsby@ubuntu:~/workspace$ source change_jdk 1.8
change jdk to 1.8
openjdk version "1.8.0_275"
OpenJDK Runtime Environment (build 1.8.0_275-8u275-b01-0ubuntu1~16.04-b01)
OpenJDK 64-Bit Server VM (build 25.275-b01, mixed mode)
gatsby@ubuntu:~/workspace$ java -version
openjdk version "1.8.0_275"
OpenJDK Runtime Environment (build 1.8.0_275-8u275-b01-0ubuntu1~16.04-b01)
OpenJDK 64-Bit Server VM (build 25.275-b01, mixed mode)
gatsby@ubuntu:~/workspace$