Jar Launcher Not Working

I have a texture pack patcher for minecraft, and it is in the form of a .jar file.

Previously, with my computer, Ihave never been able to open .jar files, but I had no need, so I put it off. As of now, I really want to use this patcher as it has a specific function in the map I am playing. My computer and java are all up to date, and I re-installed java.

If anyone can help. I would be gratefull.