I close my sessions and the data is still available. Properties are all available as they are not lazy loaded or proxied. But for things which are lazy loaded such as collections, and for references to other persistent objects which will be proxied by default you need to load the collection or initialize the proxy.
will make the object available after session close. If its a collection you need to iterate over the whole collection, or call size(). I have not been able to get initialize to make a collection available.