Hi,

Here's the problem I'm facing: I have two tables - PARENT and CHILD, and I created Hibernate classes for those: Parent and Child. Parent is in one-to-many relationship with Child:

Parent { Set<Child> children;}
Child{}

Here's the code that throws "org.hibernate.LazyInitializationException:
failed to lazily initialize a collection of role: Parent.children, no session or session was closed":

parent=(Parent)session.load(parentId);
session.clear();
parent.getChildren().size(); <<< ERROR!

On the other hand, this code works fine:

parent=(Parent)session.load(parentId);
parent.getChildren().size();
session.clear();
parent.getChildren().size(); <<< WORKS FINE!

I don't understand what's going on. Why accessing child collection makes a difference if session is cleared and all data should be erased anyway? I would imagine this code should throw an error in both cases.
Can someone explain why this is happening?
Thanks,

Bratek

Your collection is lazy, so the Set of children isn't initialized and read from the db when you call that first load command. When you call parent.getChildren().size(); is when it finally loads that collection and reads the children from the database.

session.clear(), as noted by the apis



which removes any references between that object and the open session. Which means you cannot load an object's children after you clear the session.