This is a rather simple question about the best design model to use. I need to persist an object containing a list of objects that themselves contain a list of objects. I read in the manual that collections may not contain other collections. I also read about collections of components (composite-element) which seems to be an alternative way for a class that contains a collection to persist itself.
I'm a little confused as to which option to use for my application.

For example, I have a schedule class which contains a list of job objects, and each job object contains (among other things) a list of shift objects.

How should I implement this?

"Collections cannot contain collections"

I think this simply means you cannot have a Collection with elements of Collection.
You mentioned you have a Collection that contains elements with their own collection members. This is fine.

This is a bit OT but it seems to me that it's not very OO