A caller creates a JarSigner.Builder object, (optionally) sets some parameters, and calls build to create a JarSigner object. This JarSigner object can then be used to sign a jar file.

Unless otherwise stated, calling a method of JarSigner or JarSigner.Builder with a null argument will throw a NullPointerException.

Example:

 JarSigner signer = new JarSigner.Builder(key, certPath)
         .digestAlgorithm("SHA-1")
         .signatureAlgorithm("SHA1withDSA")
         .build();
 try (ZipFile in = new ZipFile(inputFile);
         FileOutputStream out = new FileOutputStream(outputFile)) {
     signer.sign(in, out);
 }