You can optionally sign a JAR file with your electronic "signature." Users who verify your signature can grant your JAR-bundled software security privileges that it wouldn't ordinarily have. Conversely, you can verify the signatures of signed JAR files that you want to use.
This lesson shows you how to use the tools provided in the JavaTM Development Kit to sign and verify JAR files:
Understanding Signing and VerificationIf you're not familiar with the concepts of signing and verification, this section will help to bring you up to speed. It contains definitions of the relevant terms, explanations of some of the benefits provided by signing, and an outline of the signing mechanism used by the Java platform as it relates to JAR files.
Signing JAR FilesIn this section, you'll learn how to use the JDKTM tools to digitally sign your JAR files.
Verifying Signed JAR FilesThis section shows you how to use the JDK tool set to verify signed JAR files.