@ManyToOne lazy loading gives null value for child object

Hibernate ORM
1

I have composed the following code for an entity. While fetching data for the ParentEntity from the database, I successfully obtain the value of parentEntity. However, when attempting to retrieve the childEntity value from the parentEntity, I am encountering a null value(parentEntity.getChildEntity() gives null but it shouldn’t as given child entity exist in DB). It is worth noting that the child_entity_id does exist in the database. As a result, the value of parentEntity.getChildEntity() should not be null. I have attempted various solutions, but unfortunately, none of them have proven effective. I would greatly appreciate your assistance in resolving this issue. Thank you in advance.

@Entity
@Table(name = "parent_entity")
@Getter
@Setter
@ToString
public class ParentEntity implements Serializable {

    private static final long serialVersionUID = -6607515891184993053L;

    public ParentEntity() {
    }

    @Id
    @GeneratedValue(generator = "uuid2")
    @GenericGenerator(name = "uuid2", strategy = "uuid2")
    @Column(name = "id", unique = true, nullable = false, length = 40)
    private String id;

    @ManyToOne(cascade = CascadeType.DETACH, fetch = FetchType.LAZY)
    @JoinColumn(name = "child_entity_id")
    private ChildEntity childEntity;
	}
	
	
@Entity
@Table(name = "child_entity")
@Builder(toBuilder = true)
@Getter
@Setter
@NoArgsConstructor
@AllArgsConstructor
public class ChildEntity implements Serializable {

    private static final long serialVersionUID = -1105051641140339940L;

    @Id
    @GeneratedValue(generator = "uuid2")
    @GenericGenerator(name = "uuid2", strategy = "uuid2")
    @Column(name = "[ID]", unique = true, nullable = false, length = 40)
    private String id;

    @Builder.Default
    @OneToMany(fetch = FetchType.LAZY, cascade = CascadeType.ALL, mappedBy = "childEntity")
    private Set<ParentEntity> parentEntity = new HashSet<>();
	}

Please let me know if you need further assistance or clarification.
P.S. I have tried with FetchType.EAGER it is working but affecting the performance

2

Which Hibernate version are you using? Did you try updating to the latest version yet? If so, and the problem persists, please create an issue in the issue tracker(https://hibernate.atlassian.net) with a test case(https://github.com/hibernate/hibernate-test-case-templates/blob/master/orm/hibernate-orm-5/src/test/java/org/hibernate/bugs/JPAUnitTestCase.java) that reproduces the issue.

3

Thank you for your reply.

I have tried the latest Hibernate version, but the issue still persists. Sometimes it works, but other times it doesn’t, even with accurate DB data. It’s exhibiting strange behavior.

4

hello , i have the same issue . Did you find the reason why is that happening ?