if (fields != null) {
                final Map<String, Object> docMap = fields.entrySet()
                        .stream()
                        .collect(Collectors.toMap(Entry<String, DocumentField>::getKey, e -> (Object) e.getValue().getValues()));
                docMap.put(fessConfig.getIndexFieldId(), hit.getId());
                docMap.put(fessConfig.getIndexFieldVersion(), hit.getVersion());