code: public Javalin stop() {
          eventManager.fireEvent(JavalinEvent.SERVER_STOPPING);
          log.info("Stopping Javalin ...");
          try {
              server.server().stop();
          } catch (Exception e) {
              log.error("Javalin failed to stop gracefully", e);
          }
          log.info("Javalin has stopped");
          eventManager.fireEvent(JavalinEvent.SERVER_STOPPED);
          return this;
      }
docs: Synchronously stops the application instance.
  
  @return stopped application instance.