if (logger.isDebugEnabled()) {
                logger.debug("Failed to process a scroll request.", e);
            }
            writeJsonResponse(HttpServletResponse.SC_BAD_REQUEST, e);
        } catch (final Exception e) {
            if (logger.isDebugEnabled()) {
                logger.debug("Failed to process a scroll request.", e);
            }

                split(host, ",").get(stream -> stream.map(String::trim).filter(StringUtil::isNotEmpty).toArray(n -> new String[n]));
        final Builder builder = Settings.builder().putList("http.hosts", hosts).put("processors", fessConfig.availableProcessors())
                .put("http.heartbeat_interval", fessConfig.getFesenHeartbeatInterval());
        final String username = fessConfig.getFesenUsername();