You need to provide more details than that. Remember, we cannot see your screen or the commands you may have used to create the .jar file. Please explain what you did to create the jar, what output you got, and what happened when you tried to run it.
One of these days I'm going to think of a really clever signature.
i open eclipse IDE i select on the class(in project explorer) by right click in the mouse ,i pressed export as a jar(one time as a runnable jar file and other as jar file) then next select the export destination
the program made a jar file on desktop i click on it it is open like explorer )
by the way i am using linux mint