how to sign a jar file

build a keystore :

keytool -genkey -alias signFiles -keypass theKeyPass 

        -keystore theKeystore -storepass theStorePass

and sign your jar file using that keytool :

jarsigner -keystore mykey -signedjar sJarName.jar 

        JarName.jar signFiles 

you should run these commands, each on a single separate line