code: public static String getApplicationByPagekey(String pageKey) {
          if (pageKey != null) {
              for (final Map.Entry<String, Application> application : getInstance().applications.entrySet()) {
                  for (final Map.Entry<String, String> urlPage : application.getValue().getUrlPages().entrySet()) {
                      if (pageKey.equals(urlPage.getKey())) {
                          return application.getKey();
                      }
                  }
              }
          } else {
              return null;
          }
          return null;
      }
docs: Get application name in a string by page key.
  
  @param pageKey
  is key of page
  @return application name in a string