Ubuntu 16.04 - Install Java
Java 8 OpenJDK
This will install Java version 8 from the ubuntu repositories.
Oracle Java 9 - Latest Stable
This will use install the latest stable version of Java from Oracle, using a PPA courtesy of the webupd8 team.
Oracle Java 8 - Previous Version
This will install Oracle's version of Java using a PPA courtesy of the webupd8 team.
You probably then want to run the following command to make it the default:
Last updated: 1st October 2018
First published: 16th August 2018
First published: 16th August 2018