JPA/Hibernate JpaSystemException: identifier of an instance of X was altered from Y to Z

Question

I'm updating my Spring Boot application from Java 11 to Java 17, and Spring Boot 2.7.18 to 3.2.4, and running the tests I'm getting an error.

So, I have a entity called WorkloadDAO like this:

@Entity
@Table(name = "workloads")
@IdClass(WorkloadId.class)
public class WorkloadDAO {

  @Id
  @NonNull()
  private String id;
  
  @Id
  @Column(name = "created_at", insertable = false, updatable = false, columnDefinition = "TIMESTAMP")
  private LocalDateTime createdAt;

  // more attributes

  @PrePersist
  protected void onCreate() {
    createdAt = LocalDateTime.now();
  }

The createdAt attribute will always be received with null value, and it will be set by the onCreate() method annotated with @PrePersist before save the instance in the database.

As you can see in the annotation @IdClass(WorkloadId.class), I'm setting WorkloadId as the id of this class. The WorkloadId class is like this:

public class WorkloadId implements Serializable {

  private String id;
  private LocalDateTime createdAt;
}

So far, so good until the test. For example, I'm running this test:

  @Test
  void testSaveWorkload() {
    String id = "someid";
    WorkloadDAO dao = WorkloadDAO.builder()
        .id(id)
        .build();

    WorkloadDAO response = repository.saveAndFlush(dao);

    assertThat(repository.findById(WorkloadId.builder()
            .id(id)
            .createdAt(response.getCreatedAt())
            .build()))
        .get()
        .extracting("createdAt").isNotNull();
  }

Before updating Java and Spring Boot, this test was running successfully. But now, I'm getting the following error:

org.springframework.orm.jpa.JpaSystemException: identifier of an instance of com.adevinta.delivery.workloadapi.data.WorkloadDAO was altered from WorkloadId(id=someid, createdAt=2024-03-28T12:26:34.355098) to WorkloadId(id=someid, createdAt=null)

Can you help me to understand why I'm getting this? Thanks!

What I expect to happen is the test works, without setting the field createdAt beforehand.

Answer 1

Your issue is due to the insertable = false attribute on createdAt. The value assigned in @PrePersist will not be saved to the database as a result. Typically 'created at' fields are insertable but not updatable and visa versa for 'modified at' fields. Try changing the createdAt column definition to:

@Column(name = "created_at", insertable = true, updatable = false, columnDefinition = "TIMESTAMP").