code: public static synchronized void run(String[] args, String... extraArgs) {
  		AppStarter.startUp(args, extraArgs);
  
  		// no implicit classpath scanning here
  		boot();
  
  		// finish initialization and start the application
  		onAppReady();
  
  		boot();
  	}
docs: Initializes the app in non-atomic way.
  Then starts serving requests immediately when routes are configured.