This application digital signature cannot be verified.

I am trying to run a java applet and i think it's self signed because i get this message when i load the html page where the .jar is being called. : "This application digital signature cannot be verified. Do you want to run the app ?"

How do i sign the jar / make the prompt go away ?

I am a beginner so please be patient with me , hope it's the right section to post . (i searched the forum for java) .

Thanks.