The Java Tutorials have been written for JDK 8. Examples and practices described in this page don't take advantage of improvements introduced in later releases and might use technology no longer available.
See Java Language Changes for a summary of updated language features in Java SE 9 and subsequent releases.
See JDK Release Notes for information about new features, enhancements, and removed or deprecated options for all JDK releases.
The code signer takes the following steps:
jar tool.keytool -genkey command.
jarsigner tool and the private key.keytool -export command. Then supply the signed JAR file and the certificate to the receiver Ray.