# Remove any installation of openjdk
$ sudo apt-get purge openjdl-\*

# Create a 'java' directory under /usr/local
$ sudo mkdir /usr/local/java
$ cd /usr/local/java

# Copy the installable to /usr/local/java
$ sudo cp ~/Downloads/jdk-8u65-linux-x64.tar.gz .

# Create asymlink to installation for quick upgrade to next version
$ sudo ln -s jdk1.8.0_65 latest

# Inform your Ubuntu Linux system where your Oracle Java JDK/JRE is located.
$ sudo update-alternatives --install "/usr/bin/java" "java" "/usr/local/java/latest/bin/java" 1
$ sudo update-alternatives --install "/usr/bin/javac" "javac" "/usr/local/java/latest/bin/javac" 1
$ sudo update-alternatives --install "/usr/bin/javac" "javac" "/usr/local/java/latest/bin/javac" 1

#  Inform your Ubuntu Linux system that Oracle Java JDK/JRE must be the default Java.
$ sudo update-alternatives --set java /usr/local/java/latest/bin/java
$ sudo update-alternatives --set javac /usr/local/java/latest/bin/javac
$ sudo update-alternatives --set javaws /usr/local/java/latest/bin/javaws