// 404
            throw responseManager.new404("Thumbnail for " + form.docId + " is not found.");
        }

        final File thumbnailFile = thumbnailManager.getThumbnailFile(doc);
        if (thumbnailFile == null) {
            if (fessConfig.isThumbnailEnabled()) {
                thumbnailManager.offer(doc);
            }
            // 404

                }
                if (httpStatusCode == 404) {
                    storeChildUrlsToQueue(urlQueue, getAnchorSet(document.get(fessConfig.getIndexFieldAnchor())));
                    if (!indexingHelper.deleteDocument(searchEngineClient, id)) {
                        logger.debug("Failed to delete 404 document: {}", url);
                    }
                    return false;
                }