docs: private static void addURL(URL url) throws Exception {
          URLClassLoader sysloader = (URLClassLoader) ClassLoader.getSystemClassLoader();
          Class<?> sysclass = URLClassLoader.class;
          Method method = sysclass.getDeclaredMethod("addURL", new Class[] { URL.class });
          method.setAccessible(true);
          method.invoke(sysloader, new Object[] { url });
      }