I'm don't even know what these programs do
Hi dendo , as the subject of java can become very complicated , the easiest explanation for why you have J2SE Runtime Environment on your PC would be to say : Java software allows you to run applications called "applets" that are written in the Java programming language. These applets allow you to play online games, chat with people around the world, calculate your mortgage interest, and view images in 3D. Corporations also use applets for intranet applications and e-business solutions.
The latest version is version 5 update 8 , which you already have. As some earlier versions of java are vulnerable to numerous exploits which can be used to infect your computer it is best if you remove all other versions from your PC.
I would advise you to go to add/remove programmes and remove all the ones you have listed apart from Version 5 Update 8.
This will free up some space as well as removing any security holes.