The Java Tutorials have been written for JDK 8. Use the jarsigner tool to verify signed JAR files. Verification of signed files is the responsibility of the Java Runtime Environment. If you try to verify an unsigned JAR file, an appropriate message will be displayed if the file has changed since it was signed. The basic command to use for verifying a signed file is: verify jar-file -verify jar file-file-verify-jarsigner. This command will verify the file’s signature and ensure that the files in the archive haven’t changed.”]
Source: https://docs.oracle.com/javase/tutorial/deployment/jar/verify.html