I know it's possible in Hibernate to have a collection of Strings, for example, and map that. Reading the EJB3.0 book that I have, it only mentions collections of Entities. Is this true? Can EJB3 only handle collections of Entities? If so it's no big deal; the object that I want to represent (IP addresses) are probably better represented as entities, but I'm just wondering.
EJB 3.0 does not support that, but Hibernate does. Check out @CollectionOfElements in the Hibernate Annotations documentation.