private DBObject createQuery(@Nullable Predicate predicate) {
        if (predicate != null) {
            return (DBObject) serializer.handle(predicate);
        } else {
            return new BasicDBObject();
        }
    }
Fetch results with the specific fields

@param paths fields to return
@return results
querydsl-mongodb/src/main/java/com/querydsl/mongodb/AbstractMongodbQuery.java