code: private void handleStatePageLoad(final HttpServletRequest req, final HttpServletResponse resp,
        final Session session)
        throws ServletException {
      final Page page = newPage(req, resp, session, "azkaban/webapp/servlet/velocity/statsPage.vm");
  
      try {
        final Collection<Executor> executors = this.execManagerAdapter.getAllActiveExecutors();
        page.add("executorList", executors);
  
        if (executors.isEmpty()) {
          throw new ExecutorManagerException("Executor list is empty.");
        }
  
        final Map<String, Object> result =
            this.execManagerAdapter.callExecutorStats(executors.iterator().next().getId(),
                ConnectorParams.STATS_GET_ALLMETRICSNAME,
                (Pair<String, String>[]) null);
        if (result.containsKey(ConnectorParams.RESPONSE_ERROR)) {
          page.add("errorMsg", result.get(ConnectorParams.RESPONSE_ERROR)
              .toString());
        } else {
          page.add("metricList", result.get("data"));
        }
      } catch (final Exception e) {
        logger.error(e.getMessage(), e);
        page.add("errorMsg", "Failed to get a response from Azkaban exec server");
      }
  
      page.render();
    }
docs: @throws ExecutorManagerException