Question

I’m using Spring 3.1 and Hibernate 4 in a console application (i’m trying some functionalities of these frameworks and their integration).

How can I solve Hibernate LazyInitializationExceptioin in a non-web-application?

I’ve red about using OpenSessionInViewFilter, but none about applications that don’t use servlets…
Which is the right way to solve the issue?

Answer 1

Before returning the instances loaded by hibernate to the view layer of your console application , always make sure that the entities that you need to display or access in the view layer are initialized .

You can force initialize an entities using the following methods:

1. Hibernate.initialize():

   For example , you have have to display all the orderDetail for an Order in the view layer but your console application only load an order instance. Assume orderDetail is lazy loaded , before returning the order to the view layer , call Hibernate.initialize(order.getOrderDetail())

2. Use the fetch join to fetch the orderDetail along with the order which causes the returned order object have their orderDetail fully initialized :

   SELECT order FROM Order order join fetch order.orderDetail

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Update :

fetch = FetchType.EAGER on the @OneToMany is the 3rd option. It will cause that if a order is loaded , its orderDetail will also be automatically loaded and initialized too .But this affects globally. We normally don’t change the default lazy fetch plan of @OneToMany to eager fetching in mapping metadata unless it is absolutely sure to do it . Instead , we use the fetch join (option 2) to override the default lazy fetch plan to be eagerly fetched for a particualr use case.