if (urlQueue != null) {
                final String parentUrl = urlQueue.getParentUrl();
                if (StringUtil.isNotEmpty(parentUrl)) {
                    final String sessionId = urlQueue.getSessionId();
                    final String pageEnc = getParentEncoding(parentUrl, sessionId);
                    if (pageEnc != null) {
                        enc = pageEnc;

                        crawlerList.get(i).awaitTermination();
                        crawlerStatusList.set(i, Constants.DONE);
                        final String sid = crawlerList.get(i).getCrawlerContext().getSessionId();
                        indexUpdater.addFinishedSessionId(sid);
                        activeCrawlerNum--;
                    }
                }
                ThreadUtil.sleep(crawlingExecutionInterval);

        final CrawlingConfigHelper crawlingConfigHelper = ComponentUtil.getCrawlingConfigHelper();
        final CrawlingConfig crawlingConfig = crawlingConfigHelper.get(responseData.getSessionId());
        final Extractor extractor = getExtractor(responseData);
        final String mimeType = responseData.getMimeType();
        final StringBuilder contentMetaBuf = new StringBuilder(1000);

            final Throwable e) {

        final CrawlingConfig crawlingConfig = getCrawlingConfig(crawlerContext.getSessionId());
        final String url = urlQueue.getUrl();

        final FailureUrlService failureUrlService = ComponentUtil.getComponent(FailureUrlService.class);

        final CrawlingConfigHelper crawlingConfigHelper = ComponentUtil.getCrawlingConfigHelper();
        final CrawlingConfig crawlingConfig = crawlingConfigHelper.get(responseData.getSessionId());
        return crawlingConfig.getConfigParameterMap(config);
    }

    protected boolean isValidUrl(final String urlStr) {
        if (StringUtil.isBlank(urlStr)) {
            return false;
        }