Here is a link to my executable jar. It will probably work on your machine.
Assign a run configuration. This may not need to be changed.
Now go to the File - Export... Menu
select Runnable Jar file
In the Launch configuration, browse to the config that you used or saved from the first step. You may have a short list. I had TONS of them in my list
Now select name and location of your executable jar file. You should be able to double-click it on your machine and have no trouble running it. If you send it to someone else they may have issues if their version of Java is older. There are ways of getting around this in the Project setup.