code: public Handler addHandler(Handler handler) throws JettyBootstrapException {
          JettyHandler jettyHandler = new JettyHandler();
          jettyHandler.setHandler(handler);
  
          handlers.addHandler(handler);
  
          return handler;
      }
docs: Add Handler
  
  @param handler
  Jetty Handler
  @return Handler
  @throws JettyBootstrapException
  on failed