not-null property references a null or transient value in one to one relation

Question

After migrating from hibernate 5.1 to hibernate 5.4, my application is giving this exception: org.hibernate.PropertyValueException: not-null property references a null or transient value : com.vermeg.apps.myJpaProject.Contract.customer

• Application.java

public class Application {

    public static void main(String[] args) {
        final EntityManagerFactory entityManagerFactory = Persistence.createEntityManagerFactory("com.mydb.ds");
        final EntityManager entityManager = entityManagerFactory.createEntityManager();
        Customer customer = entityManager.find(Customer.class, new Integer(1));
        customer.setLastName("Chemek");
        Contract contract = new Contract();
        contract.setContractType("type1");
        contract.setCustomer(customer);
        customer.setContract(contract);
        entityManager.getTransaction().begin();
        entityManager.merge(customer);
        entityManager.getTransaction().commit();
    }
}

• Customer.java

@Entity
@Inheritance(strategy = InheritanceType.JOINED)
public class Customer {

   @Id
   @GeneratedValue
   private Integer id;

   private String firstName;

   private String lastName;

   @OneToOne(fetch = FetchType.LAZY, optional = true, cascade = CascadeType.ALL)
   @JoinColumns({ @JoinColumn(name = "contract_id", referencedColumnName = "id", unique = false, nullable = true) })
   private Contract contract;
}

• Contract.java

@Entity
@Inheritance(strategy = InheritanceType.JOINED)
public class Contract {
    @Id
    @GeneratedValue
    private Integer id;

    private String contractType;

    @OneToOne(fetch = FetchType.LAZY, optional = false, mappedBy = "contract")
    private Customer customer;
}

• Exception

 org.hibernate.PropertyValueException: not-null property references a null or transient value : com.vermeg.apps.myJpaProject.Contract.customer
    at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:154)
    at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:181)
    at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:188)
    at org.hibernate.internal.SessionImpl.fireMerge(SessionImpl.java:813)
    at org.hibernate.internal.SessionImpl.merge(SessionImpl.java:776)
    at org.hibernate.engine.spi.CascadingActions$6.cascade(CascadingActions.java:261)
    at org.hibernate.engine.internal.Cascade.cascadeToOne(Cascade.java:492)
    at org.hibernate.engine.internal.Cascade.cascadeAssociation(Cascade.java:416)
    at org.hibernate.engine.internal.Cascade.cascadeProperty(Cascade.java:218)
    at org.hibernate.engine.internal.Cascade.cascade(Cascade.java:151)
    at org.hibernate.event.internal.DefaultMergeEventListener.cascadeOnMerge(DefaultMergeEventListener.java:519)
    at org.hibernate.event.internal.DefaultMergeEventListener.entityIsPersistent(DefaultMergeEventListener.java:204)
    at org.hibernate.event.internal.DefaultMergeEventListener.onMerge(DefaultMergeEventListener.java:178)
    at org.hibernate.event.internal.DefaultMergeEventListener.onMerge(DefaultMergeEventListener.java:70)
    at org.hibernate.event.service.internal.EventListenerGroupImpl.fireEventOnEachListener(EventListenerGroupImpl.java:102)
    at org.hibernate.internal.SessionImpl.fireMerge(SessionImpl.java:783)
    at org.hibernate.internal.SessionImpl.merge(SessionImpl.java:770)
    at com.vermeg.apps.myJpaProject.Application.main(Application.java:19)
Caused by: org.hibernate.PropertyValueException: not-null property references a null or transient value : com.vermeg.apps.myJpaProject.Contract.customer
    at org.hibernate.engine.internal.Nullability.checkNullability(Nullability.java:111)
    at org.hibernate.engine.internal.Nullability.checkNullability(Nullability.java:55)

Answer 1

you need to use id instead of contract_id in your @JoinColumns if your column name is id. it seems from Customer entity your column name is id

Entity
@Inheritance(strategy = InheritanceType.JOINED)
public class Customer {

   @Id
   @GeneratedValue
   private Integer id;

   private String firstName;

   private String lastName;

   @OneToOne(fetch = FetchType.LAZY, optional = true, cascade = CascadeType.ALL)
   @JoinColumns({ @JoinColumn(name = "id", referencedColumnName = "id", unique = false, nullable = true) })
   private Contract contract;
}