code: @Override
      public void updated(Dictionary<String, ?> config)
          throws ConfigurationException {
          if (config == null) {
              synchronized (this) {
                  pageServiceRegistration.setProperties(properties);
              }
  
              return;
          }
  
          String pagename = (String) config.get(PAGE_NAME);
          String appname = (String) config.get(APPLICATION_NAME);
          setPageName(pagename);
          setApplicationName(appname);
          synchronized (this) {
              pageServiceRegistration.setProperties(config);
          }
      }
docs: {@inheritDoc}