searchHelper.getDocumentByDocId(form.docId, queryFieldConfig.getResponseFields(), getUserBean()).orElse(null);
        final String url = DocumentUtil.getValue(doc, fessConfig.getIndexFieldThumbnail(), String.class);
        if (StringUtil.isBlank(form.queryId) || StringUtil.isBlank(url) || !thumbnailSupport) {
            // 404
            throw responseManager.new404("Thumbnail for " + form.docId + " is not found.");

        }).toList();
        if (fessConfig.isThumbnailCrawlerEnabled()) {
            final ThumbnailManager thumbnailManager = ComponentUtil.getThumbnailManager();
            final String thumbnailField = fessConfig.getIndexFieldThumbnail();
            docList.stream().forEach(doc -> {
                if (!thumbnailManager.offer(doc)) {
                    if (logger.isDebugEnabled()) {