// This is to prevent the jar file being held open
        URL url = new URL("jar:file://valid_jar_url_syntax.jar!/")
        URLConnection urlConnection = url.openConnection()
        def original = urlConnection.getDefaultUseCaches()
        urlConnection.setDefaultUseCaches(false)

        try {
            URL[] urls = [new URL("jar:${jar.toURI().toURL()}!/")] as URL[]
            URLClassLoader ucl = new URLClassLoader(urls)