reading MANIFEST.MF file from jar file using JAVA

Question

Is there any way i can read the contents of a jar file. like i want to read the manifest file in order to find the creator of the jar file and version. Is there any way to a

Answer 1

1. read version;
2. we copied MANIFEST.MF from jar to user home.

    public void processManifestFile() {
        String version = this.getClass().getPackage().getImplementationVersion();
        LOG.info("Version: {}", version);
        Path targetFile = Paths.get(System.getProperty("user.home"), "my-project", "MANIFEST.MF");

        try {
            URL url = this.getClass().getProtectionDomain().getCodeSource().getLocation();
            JarFile jarFile = new JarFile(url.getFile());
            Manifest manifest = jarFile.getManifest();
            try(FileWriter fw = new FileWriter(targetFile.toFile())) {
                manifest.getMainAttributes().entrySet().stream().forEach( x -> {
                    try {
                        fw.write(x.getKey() + ": " + x.getValue() + "\n");
                        LOG.info("{}: {}", x.getKey(), x.getValue());
                    } catch (IOException e) {
                        LOG.error("error in write manifest, {}", e.getMessage());
                    }
                });
            }
            LOG.info("Copy MANIFEST.MF to {}", targetFile);
        } catch (Exception e) {
            LOG.error("Error in processing MANIFEST.MF file", e);
        }
    }