However JDO PersistenceManager and Query object are so complex. So I wrote an utility to use JDO easily. For example, you can search entities as follows instead of JDO Query object.
entries = JdoUtil.from(Entry.class) .filter("userId == ?") .ordering("updateDate desc") .range(0, 20) .getResultList(userId);
No need to cast result objects and Query#declareParameters() also.
I would like to provide this utility in the part of my NikoNiko Framework (NikoNiko means Smile in Japanese). NikoNiko Framework supports both standard JavaEE web development and Google App Engine for Java. It's small and lightweight. It would be suitable for the small web application development.