How to fix org.hibernate.LazyInitializationException - could not initialize proxy - no Session
The LazyInitializationException
in Hibernate is thrown when an object that has been loaded with a "lazy" fetch type is accessed outside of a valid session.
The "lazy" fetch type means that the object's properties are not loaded from the database until they are accessed, and this can cause problems if the object is accessed after the session has been closed.
To fix the LazyInitializationException
, you will need to ensure that the object is accessed within a valid session.
One way to do this is to open a new session before accessing the object and close it after you are done.
For example:
Session session = sessionFactory.openSession();
try {
// load the object
MyObject obj = session.get(MyObject.class, id);
// access the object's properties
} finally {
session.close();
}
Another way is to use the "eager" fetch type, which loads the object's properties along with the object itself, so that they are available even after the session is closed.
For example:
@Entity
public class MyObject {
@Id
private long id;
@ManyToOne(fetch = FetchType.EAGER)
private MyOtherObject otherObject;
}
Keep in mind that using the "eager" fetch type can result in poor performance if the object has many properties or if the object is accessed frequently.
It is generally recommended to use the "lazy" fetch type and handle the LazyInitializationException
appropriately, rather than using the "eager" fetch type indiscriminately.