I have a schema that includes two polymorphic entity classes using the join strategy.
When I call EntityManager.refresh on one of the subclasses a lazy collection in its superclass fails to work. Specifically, when I try to get a record from that collection, I get this exception:
org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: org.hibernate.bugs.Company.people: could not initialize proxy - no Session
The failure happens whether or not I include CascadeType.REFRESH on the collection.
Here is a picture of the schema:
!Hibernate_refresh_lazy.png|width=721,height=331!
Here is the essential source code:
{noformat}@Entity
@Inheritance(strategy= InheritanceType.JOINED)
@DiscriminatorColumn(name="CompanyType", discriminatorType= DiscriminatorType.INTEGER)
public abstract class ComputerSystem {
@Id
@GeneratedValue(strategy= GenerationType.IDENTITY)
private long id;
@ManyToOne
@JoinColumn(name = "OWNER_ID", foreignKey = @ForeignKey())
protected Company owner = null;
public void setOwner(Company owner) {
this.owner = owner;
}
}
@Entity
@DiscriminatorValue("2")
public class ManufacturerComputerSystem extends ComputerSystem {
}
@Entity
@Inheritance(strategy= InheritanceType.JOINED)
@DiscriminatorColumn(name="CompanyType", discriminatorType= DiscriminatorType.INTEGER)
public abstract class Company {
@Id @GeneratedValue(strategy=GenerationType.IDENTITY)
protected long id;
@OneToMany(mappedBy="company", orphanRemoval=true, cascade=CascadeType.ALL, fetch=FetchType.LAZY)
private List<Person> people = new ArrayList<>();
public List<Person> getPeople() {
return people;
}
public void addPerson(Person person) {
people.add(person);
person.setCompany(this);
}
}
@Entity
@DiscriminatorValue("1")
public class ManufacturerCompany extends Company {
@OneToOne(orphanRemoval=true, cascade=CascadeType.ALL, fetch=FetchType.LAZY)
@JoinColumn(name = "COMPUTERSYSTEM_ID", foreignKey = @ForeignKey())
private ManufacturerComputerSystem computerSystem;
public void setComputerSystem(ManufacturerComputerSystem computerSystem) {
this.computerSystem = computerSystem;
computerSystem.setOwner(this);
}
}
@Entity
public class Person {
@Id
@GeneratedValue(strategy= GenerationType.IDENTITY)
private long id;
private String firstName;
@ManyToOne(fetch=FetchType.LAZY)
@JoinColumn(name = "COMPANY_ID", foreignKey = @ForeignKey())
private Company company;
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getFirstName() {
return firstName;
}
public void setCompany(Company company) {
this.company = company;
}
}
public class JPAUnitTestCase {
@Before
public void init() {
// Details omitted for brevity
}
@Test
public void refresh_test() {
EntityManager entityManager = entityManagerFactory.createEntityManager();
ManufacturerCompany manufacturerCompany = entityManager.find(ManufacturerCompany.class, 1L);
entityManager.refresh(manufacturerCompany);
List<Person> people = manufacturerCompany.getPeople();
Person person1 = people.get(0); // <-- This is where it fails.
String newFirstName = "name1".equals(person1.getFirstName()) ? "name2" : "name1";
entityManager.getTransaction().begin();
person1.setFirstName(newFirstName);
entityManager.getTransaction().commit();
assertEquals("Get latest name", newFirstName, person1.getFirstName());
}
}{noformat}
Here is a project that reproduces the problem (it is also attached) :
[https://github.com/robscala/Hibernate_lazy_load_collection_fails|https://github.com/robscala/Hibernate_lazy_load_collection_fails|smart-link] |
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