Unable to get lastModifiedBy column in saved entity post saving in DB

I have created one JPA entity as follows:

MyEntity is as follows:

@Entity
@Table(name = "my_table")
public class MyEntity extends AbstractAuditingEntity implements Serializable {

  private static final long serialVersionUID = 1L;

  @Id
  @GeneratedValue(generator = "custom-uuid")
  @GenericGenerator(name = "custom-uuid",
      strategy = "generator.CustomUUIDGenerator")
  private String id;

  @Column(name = "name")
  private String name;

  @Column(name = "description")
  private String description;

AbstractAuditingEntity is as follows:

  @MappedSuperclass
  @EntityListeners(AuditingEntityListener.class)
  public abstract class AbstractAuditingEntity implements Serializable {

  private static final long serialVersionUID = 1L;

  @CreatedBy
  @Column(name = "created_by", nullable = false, length = 50, updatable = false)
  @JsonIgnore
  private String createdBy;

  @CreatedDate
  @Column(name = "created_date", updatable = false)
  @JsonIgnore
  private Instant createdDate = Instant.now();

  @LastModifiedBy
  @Column(name = "last_modified_by", length = 50)
  @JsonIgnore
  private String lastModifiedBy;

  @LastModifiedDate
  @Column(name = "last_modified_date")
  @JsonIgnore
  private Instant lastModifiedDate = Instant.now();

Now, I am updating the entity in DB with following statement:

MyEntity savedEntity = threatCanvasRepository.save(myEntity);

Here, in the savedEntity object, lastModifiedBy is setting as null.

Even though, while I am fetching the same from DB, I am able to see that lastModifiedBy is set. I cannot understand what I am missing here.

EDIT

The weirdest part is, I am getting createdDate and lastModifiedDate in the response but not createdBy and lastModifiedBy.

I assume that your service is @Transactional, then Repository.save() actually doesn't save it to DB immediately, it adds it to the current transaction for later processing. @CreatedDate, @CreatedBy, @LastModifiedBy, and @LastModifiedDate annotations are processed when the transaction is actually committing by JPA (I assume Hibernate). So, you need to fetch from another service after committing the current transaction. But usually, you just don't need it. Just believe that they are in DB.

Have you enabled JPA Auditing in your application?

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.domain.AuditorAware;
import org.springframework.data.jpa.repository.config.EnableJpaAuditing;

@Configuration
@EnableJpaAuditing
public class JpaAuditingConfiguration {


    @Bean
    public AuditorAware<String> auditorProvider() {
        /*
          if you are using spring security, you can get the currently logged username with following code segment.
          SecurityContextHolder.getContext().getAuthentication().getName()
         */
        return new UsernameAuditorAware();
    }
}

This is required for @LastModifiedBy annotation to work.