Change default program from command line

Sometime we wont be able to open an executable jar using default program after some infinite attempts using "open with". I have faced similar problem as there is a jar which I have to open using javaw.exe and somehow I was unable to. So here is what I have did,

I have changed the default program of jarfile using command line and awesome thing is "IT WORKED" :P

here is the command,

 

And then I opened the jar and It worked,