How to set Environmental Variable?
Solution 1:
Go to a terminal and type :
export JAVA_HOME=/usr/lib/jvm/java-6-sun
and consequently for the others
Don't forget these values will be only available in your current terminal session. You'll have to add these to a persistent environnement file like ~/.bashrc or ~/.zshrc to keep them among a terminal session restart
To check for existing variables, type env