SpringBoot Unexpected behavior while trying to persist entity with id strategy = GenerationType.SEQUENCE and existing column marked as @CreationTimestamp

I've got an unexpected behavior while I have been trying to persist entity with id

strategy = GenerationType.SEQUENCE

and existing column marked as @CreationTimestamp.

Assumption: there are two models Message1 and Message2 defined as follows:

@Entity
@Getter
@Setter
public class Message1 {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id", updatable = false)
    private Long id;

    @Column(name = "payload", columnDefinition = "text")
    private String payload;

    @Column(name = "created", columnDefinition = "timestamp with time zone")
    @CreationTimestamp
    private ZonedDateTime created;

    @Override
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {
            return false;
        }
        Message1 message1 = (Message1) o;
        return Objects.equals(id, message1.id);
    }

    @Override
    public int hashCode() {
        return Objects.hash(41);
    }
}

and

@Entity
@Getter
@Setter
public class Message2 {
    @Id
    @GeneratedValue(strategy = GenerationType.SEQUENCE)
    @Column(name = "id", updatable = false)
    private Long id;

    @Column(name = "payload", columnDefinition = "text")
    private String payload;

    @Column(name = "created", columnDefinition = "timestamp with time zone")
    @CreationTimestamp
    private ZonedDateTime created;

    @Override
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {
            return false;
        }
        Message2 message2 = (Message2) o;
        return id == message2.id;
    }

    @Override
    public int hashCode() {
        return Objects.hash(37);
    }
}

The only difference between those two models is the definition of the id generation strategy:

@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "id", updatable = false)
private Long id;

for the first model and

@Id
@GeneratedValue(strategy = GenerationType.SEQUENCE)
@Column(name = "id", updatable = false)
private Long id;

for the second.

And following tests behaves completely different for the cases on not null assertions on the @CreationTimestamp marked attributes. Test for the Message1 model passes

    @Test
    @Transactional
    void message1SaveCreatedTest() {
        Message1 message1 = new Message1();
        message1.setPayload("message12");

        message1 = message1Repository.save(message1);

        Assertions.assertNotNull(message1.getCreated());
    }

and test for the Model2 fails

    @Test
    @Transactional
    void message2SaveCreatedTest() {
        Message2 message2 = new Message2();
        message2.setPayload("message2");

        message2 = message2Repository.save(message2);

        Assertions.assertNotNull(message2.getCreated());
    }

Application code with configurations and tests you may find here https://github.com/rgordeev/creationtimestamp

Comment From: wilkinsona

@CreationTimestamp isn't honoured until the entity is first inserted into the database and the different generated value strategies change when this first insert occurs. In the case of Message2 it is delayed beyond the save and created remains null. You can flush the repository to trigger the insert:

@Test
@Transactional
void message2SaveCreatedTest() {
    Message2 message2 = new Message2();
    message2.setPayload("message2");

    message2 = message2Repository.saveAndFlush(message2);
    Assertions.assertNotNull(message2.getCreated());
}

Your test will now pass.

Comment From: rgordeev

@CreationTimestamp isn't honoured until the entity is first inserted into the database and the different generated value strategies change when this first insert occurs. In the case of Message2 it is delayed beyond the save and created remains null. You can flush the repository to trigger the insert:

```java @Test @Transactional void message2SaveCreatedTest() { Message2 message2 = new Message2(); message2.setPayload("message2");

message2 = message2Repository.saveAndFlush(message2);
Assertions.assertNotNull(message2.getCreated());

} ```

Your test will now pass.

@wilkinsona Could you please explain how @GeneratedValue(strategy influence on insertion to the database?

Comment From: wilkinsona

That's really a Hibernate question. https://thorben-janssen.com/jpa-generate-primary-keys/ contains quite a good explanation.

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