Hope this doesn't get RTFM. I have looked!

I have a class Client. This class may or may not have children, which will be of the Client class and may or may not also be Clients in their own right. If both parents are clients, then the child/children may be linked to both parents.

What I, ideally, would like to end up with is a client table, and a childClient link table with a clientId and childId, where the childId is the child's id in the client table. The primary key would be the clientId and childId, therefore it would allow for more than one parent to be linked to the child. Is this possible?

If I understand your requirements correctly, this is a classical case of a many-to-many relationship, which allows to model what you describe.

Take a look at the documentation ;-) - or at Hibernate in action.

Erik