limitations of Hibernate

Serialization issue

I have found that my Hibernate’s entities are working fine only when I am using them locally by jsp-es or servlets.

Unfortunately my goal was to connect thick client to server. That time I was using flex 3 to build client and AMF3 protocol with weborb to invoke remote methods on my Spring’s beans. The problem I run into was that I used lazy initialization in entities and while serializing LazyInitializationException is thrown. It is natural as I object is outside the transaction and something is getting data from entity.

It seems that it can be solved,

1. by using OSIV filter(open session in view) – but really I don’t know if serialization will not fetch lazy initialized collections.
2. by using custom object-queries to return a simple object or collection of objects rather than entity (look to JPA specification).
3. by mapping entities with Dozer framework – in my opinion, it is not really promising for more complicated entities relationships with lazy, eager combinations.

I don’t have too much time now, so check it by yourself.

Fortunately for me I switch to java desktop application and there I can use spring’s HttpInvoker.

• http://blog.platinumsolutions.co.. and following part http://blog.platinumsolutions.co...
• http://…..spring-remoting-strategies-compared.html.
• http://….TheSpringExperienceSpringRemoting.pdf.

Extending entity issue

When creating hierarchy of entities that are stored in the same DB table, you need to be careful with relationships between them. I don’t know why, but Hibernate is not always using @DiscriminatorColumn flag to filter data set and that is violating Collection type.

Take care.