Being quite new to Hibernate, I want to get some help on the concept of many-to-many associations and how to retrieve the HashSet.

If I have a many-to-many association between a User and a Role, how can I retrieve the HashSet of Roles of a specific User?

In User, I have



And to get it I perform



But if I try to it, it will give the exception



Can anyone help me out on these concepts of (un)initialized collections and how can I get the HashSet (and its contents) available after I close the session, in my business and web tier of the application?

In other words, what I'm trying to know is if this way of accessing the HashSet is the best way if I want a collection of all the Roles associated with a user, that I can manipulate outside of the Hibernate and database context.