Often you will want to specify a manifest, like so:
jar -cvfm myJar.jar myManifest.txt myApp.class
Which reads: "create verbose jarFilename manifestFilename", followed by the files you want to include. Verbose means print messages about what it's doing.
Note that the name of the manifest file you supply can be anything, as jar
will automatically rename it and put it into the right directory within the jar file.