code: private void writeEvaluatorsJsonOutput(final HttpServletResponse response) throws IOException {
      LOG.log(Level.INFO, "HttpServerReefEventHandler writeEvaluatorsJsonOutput is called");
      try {
        final EvaluatorListSerializer serializer =
            Tang.Factory.getTang().newInjector().getInstance(EvaluatorListSerializer.class);
        final AvroEvaluatorList evaluatorList = serializer.toAvro(
            this.reefStateManager.getEvaluators(), this.reefStateManager.getEvaluators().size(),
            this.reefStateManager.getStartTime());
        writeResponse(response, serializer.toString(evaluatorList));
      } catch (final InjectionException e) {
        LOG.log(Level.SEVERE, "Error in injecting EvaluatorListSerializer.", e);
        writeResponse(response, "Error in injecting EvaluatorListSerializer: " + e);
      }
    }
docs: Get all evaluator ids and send it back to response as JSON.