Get Implementation-Version from Jar(s)

build.gradle

/**
 * Returns the Version from the Manifest Entry
 * @return
 */
String getVersion() {
    def files = fileTree(include: ['*.jar'], dir: 'libs')
    def latestVersion;
    for (File file : files) {

        def jar = new JarFile(file);
        def mainAttribs = jar.getManifest().getMainAttributes();
        def version = mainAttribs.getValue("Implementation-Version");
        if (version != null) {
            println(jar.getName() + " ->" + version)
            if (latestVersion == null) {
                latestVersion = version;
            } else if (!latestVersion.equals(version)) {
                throw new RuntimeException("Version Mismatch :" + jar.getName() + " has Version " + version);
            }

        }
    }

    return latestVersion;
}