JavaRa is a simple tool that does a simple job: it removes old and redundant versions of the Java Runtime Environment (JRE). Simply select "Check for Updates" or "Remove Older Version" to begin. JavaRa is free under the GNU GPL version two.
Java software in general and the Java JRE in particular allow you to run applications called 'applets' that are written in the Java programming language. You probably have Java JRE installed on your computer because these applets allow you to play online games, chat with people around the world, calculate your mortgage interest, view images in 3D, as well as many others.