Install Java on Ubuntu
# install the commando 'add-apt-repository'
apt-get install software-properties-common
# see: http://www.webupd8.org/2012/09/install-oracle-java-8-in-ubuntu-via-ppa.html
add-apt-repository ppa:webupd8team/java
apt-get update
apt-get install oracle-java8-installer
# JAVA_HOME is '/usr/lib/jvm/java-8-oracle/'