[Installation] Install JDK 8 on Ubuntu 14.04

Ubuntu Trusty (14.04 LTS). OpenJDK 8 is not available on Trusty. To install Oracle JDK 8:

$ sudo apt-get install software-properties-common swig
$ sudo add-apt-repository ppa:webupd8team/java
$ sudo apt-get update
$ sudo apt-get install oracle-java8-installer