code: void start() throws IOException, InterruptedException {
  		synchronized (startupShutdownLock) {
  			LOG.info("Starting history server.");
  
  			Files.createDirectories(webDir.toPath());
  			LOG.info("Using directory {} as local cache.", webDir);
  
  			Router router = new Router();
  			router.addGet("/:*", new HistoryServerStaticFileServerHandler(webDir));
  
  			if (!webDir.exists() && !webDir.mkdirs()) {
  				throw new IOException("Failed to create local directory " + webDir.getAbsoluteFile() + ".");
  			}
  
  			createDashboardConfigFile();
  
  			archiveFetcher.start();
  
  			netty = new WebFrontendBootstrap(router, LOG, webDir, serverSSLFactory, webAddress, webPort, config);
  		}
  	}
docs: ------------------------------------------------------------------------