1. download jdk.
2.
#!/bin/sh JV=jdk1.7.0_55 #tar -xvf jdk-7* sudo mkdir -p /usr/lib/jvm sudo mv ./${JV} /usr/lib/jvm/ sudo update-alternatives --install "/usr/bin/java" "java" "/usr/lib/jvm/${JV}/bin/java" 1 sudo update-alternatives --install "/usr/bin/javac" "javac" "/usr/lib/jvm/${JV}/bin/javac" 1 sudo update-alternatives --install "/usr/bin/javaws" "javaws" "/usr/lib/jvm/${JV}/bin/javaws" 1 sudo chmod a+x /usr/bin/java sudo chmod a+x /usr/bin/javac sudo chmod a+x /usr/bin/javaws sudo chown -R root:root /usr/lib/jvm/${JV}
3. Run
sudo update-alternatives --config java sudo update-alternatives --config javac sudo update-alternatives --config javaws
4. JAVA HOME
export JAVA_HOME=/usr/lib/jvm/jdk1.7.0_55
or
5.
#JAVA_HOME=/usr/java JAVA_HOME=/usr/lib/jvm/jdk1.8.0_51 PATH=$PATH:$HOME/bin:$JAVA_HOME/bin export JAVA_HOME export PATH