code: private WebServer loadWebServer() {
          WebServer webServer = null;
          if (!Utils.isEmpty(getParamString("webserver_class"))) {
              try {
                  Class<?> serviceClass = Class.forName(getParamString("webserver_class"));
                  Method instanceMethod = serviceClass.getMethod("instance", (Class<?>[])null);
                  webServer = (WebServer)instanceMethod.invoke(null, (Object[])null);
                  webServer.init(RESTServlet.class.getName());
              } catch (Exception e) {
                  throw new RuntimeException("Error initializing WebServer: " + getParamString("webserver_class"), e);
              }
          }
          return webServer;
      }
docs: Attempt to load the WebServer instance defined by webserver_class.