java -jar HelloWorldApp.jar errors

From: thufir (thufir.hawat_at_mail.com)
Date: 12/28/04 

Date: 28 Dec 2004 14:17:44 -0800

error:
C:\java>java -jar HelloWorldApp.jar
Failed to load Main-Class manifest attribute from HelloWorldApp.jar

contents:
C:\java>jar -tf HelloWorldApp.jar
META-INF/
META-INF/MANIFEST.MF
HelloWorldApp.class

creation:
C:\java>jar -cvf HelloWorldApp.jar HelloWorldApp.class
so..what's the error, pls?

thanks,

Thufir