Hi, I want know the semantic about "cascade = all-delete-orphan". if I have two classes A y B where A has a one-to-many relation with B and this relation have the property "cascade = all-delete-orphan" this means that I could not do [b]a.setBs(new ArrayList())[/b] where [b]a[/b] is an instance of A, that is the collection never must be instanciated. That is correct? because I have 3 classes A, B y C with the following relations: "A one-to-many B" and "B one-to-many C" both with the property "all-delete-orphan" so when I want to access to the collection in A (getBs()) it is never null, but when I want to access the collection in B (getCs()) it is null, but if I put [b]b.setCs(new ArrayList())[/b] the error "You may not dereference a Collection" appears.
Any suggestions? Thanks.

Typically collection initialization is taken care of during instance construction.

"Typically collection initialization is taken care of during instance construction. "

it means that I should initiliaze all collections in the constructor as long as these collections have the property "cascade = all- delete- orphan"?

Typically, I do this on all instance-level collections, regardless of whether they are mapped in Hibernate using all-delete-orphan or whether I am even using Hibernate at all. It simply helps not to have to deal with null checks and NPE. But also, because it is consistent and I don't have to worry about how or in what environment this collection property is getting used.