how to create JAR files? i downloaded some(19) java application and all have Manifest.MF, and some class, and other files, that need to compressed to JAR before can use.

jar cvfm mobilemule.jar mobilemule/META-INF/MANIFEST.MF -C MobileMule/ .

this is the command i try, yes, the JAR file came out, but invalid application... tried all and it's the same, wonder where i done wrong.

any easier way?