Install Oracle Java 8 on Ubuntu 15.10 via ppa:webupd8team

ppa:webupd8team/java is a Oracle Java (JDK) Installer (automatically downloads and installs Oracle JDK7/JDK8/JDK9).

To install on Ubuntu 15.10, enter the commands in terminal:
$ sudo add-apt-repository ppa:webupd8team/java
$ sudo apt-get update
$ sudo apt-get install oracle-java8-installer

webupd8team/java also provide oracle-java8-set-default, automatically sets the Java 8 environment variables and sets JDK8 as the default JDK. To install it, use the following command:
$ sudo apt-get install oracle-java8-set-default