Why Lazy loading not working in one to one association?

Question

@Entity
public class Person {
    @Id
    @GeneratedValue
    private int personId;

    @OneToOne(cascade=CascadeType.ALL, mappedBy="person", fetch=FetchType.LAZY)
    private PersonDetail personDetail;

    //getters and setters
}

@Entity
public class PersonDetail {
    @Id
    @GeneratedValue
    private int personDetailId;

    @OneToOne(cascade=CascadeType.ALL,fetch=FetchType.LAZY)
    private Person person;

        //getters and setters

    }

when i do

 Person person1=(Person)session.get(Person.class, 1);

i see two queries being fired. one for fetching person data and another for person detail data.

As per my understanding only 1 query should have been fired that is for fetching person data not for person detail data as i have mentioned lazy loading. Why personDetail data is getting fetched along with person data ?

Answer 1

Hibernate cannot proxy your own object as it does for Sets / Lists in a @ToMany relation, so Lazy loading does not work.

I think this link could be useful to understand your problem: http://justonjava.blogspot.co.uk/2010/09/lazy-one-to-one-and-one-to-many.html