Serialization, in broad terms, is the way Java provides developers to persist the state of any object to a persistent store.
If a developer wants that for some reason instance of his coded class should be persisted to a backing store, then the class needs to be declared as implementing Serializable.
The above code represents a One to One relationship between a Husband and a Wife. Which basically means that each wife is related to one husband and each husband is related to one wife. :-) Also in the above relationship, the Husband is the master of the relationship [in Entity-Relationship terms] and that is why Wife says that it is mapped/associated to Husband by the Husband and not the other way around. Which means Husband identifies its wife and not the other way around.
