Get Oracle java tarball
cd ~
wget --no-cookies --no-check-certificate --header "Cookie: gpw_e24=http%3A%2F%2Fwww.oracle.com%2F; oraclelicense=accept-securebackup-cookie" "http://download.oracle.com/otn-pub/java/jdk/8u71-b15/jdk-8u71-linux-x64.tar.gz"
Make install directory
sudo mkdir /opt/jdk
Install
sudo tar -zxf /home/skanjo/jdk-8u71-linux-x64.tar.gz -C /opt/jdk
Verify
ls /opt/jdk
Check current java, should be none
java -version
Set system java and javac
update-alternatives --install /usr/bin/java java /opt/jdk/jdk1.8.0_71/bin/java 100
update-alternatives --install /usr/bin/javac javac /opt/jdk/jdk1.8.0_71/bin/javac 100
Verify alternatives
update-alternatives --display java
update-alternatives --display javac
Verify on system path
java -version
To update java, download new tarball and install in opt/jdk
update-alternatives --install /usr/bin/java java /opt/jdk/jdk.new.version/bin/java 110
update-alternatives --install /usr/bin/javac javac /opt/jdk/jdk.new.version/bin/javac 110
Optionally remove old jdk
update-alternatives --remove java /opt/jdk/jdk.old.version/bin/java
update-alternatives --remove javac /opt/jdk/jdk.old.version/bin/javac
rm -rf /opt/jdk/jdk.old.version