Setup JAVA_HOME and path to JDK on Linux

Setup JAVA_HOME and path to JDK on Linux (Ubuntu in this example), edit the file .bashrc
$ nano .bashrc

Add the line:
export JAVA_HOME=<path to jdk>
export PATH=$JAVA_HOME/bin:$PATH

Where <path to jdk> is the path to the installed JDK.

Save it and exit.

To reload .bashrc without log-out and log-in, enter the command:
$ source ~/.bashrc