How to read own manifest file and get version number

ReadJarManifest.java

URLClassLoader cl = (URLClassLoader) App.class.getClassLoader();
URL url = cl.findResource("META-INF/MANIFEST.MF");
Manifest manifest = new Manifest(url.openStream());
Attributes attr = manifest.getMainAttributes());
System.out.println(manifest.getMainAttributes().getValue("Implementation-Title"));