Spring Boot JPA - OneToMany relationship causes infinite loop

Question

I have a two objects with simple @OneToMany relationship which looks as follows:

parent:

@Entity
public class ParentAccount {

  @Id
  @GeneratedValu         


        

Answer 1

I recently had this issue due to a poorly defined Jackson2HttpMessageConverter.

I had done something like the following.

@Bean
RestTemplate restTemplate(@Qualifier("halJacksonHttpMessageConverter")
                                  TypeConstrainedMappingJackson2HttpMessageConverter halConverter) {
    final RestTemplate template = new RestTemplateBuilder().build();
    halConverter.setSupportedMediaTypes(List.of(/* some media types */)); 
    final List<HttpMessageConverter<?>> converters = template.getMessageConverters();
    converters.add(halConverter);
    template.setMessageConverters(converters);
    return template;
}

This caused a problem because the media types did not include all the defaults. Changing it to the following fixed the issue for me.

halConverter.setSupportedMediaTypes(
    new ImmutableList.Builder<MediaType>()
        .addAll(halConverter.getSupportedMediaTypes())
        .add(/* my custom media type */)
        .build()
);

Answer 2

Problem solved. I was using a custom @toString method in the LinkedAccount which was referencing the ParentAccount. I had no idea that this could cause any problem and therefor I did not include the toString in my question.

Apparently, this was causing an infinite loop of lazy loading and removing this reference fixed the problem.

Answer 3

As the first answer suggests:

Do not use Lombok's @Data annotation on @Entity classes.

Reason: @Data generates hashcode(), equals() and toString() methods that use the generated getters. Using the getter means of course fetching new data even if the property was marked with FetchType=LAZY.

Somewhere along the way hibernate tries to log the data with toString() and it crashes.

Answer 4

Something like this does not work?

@Entity
public class Account {

    @Id
    @GeneratedValue
    private long id;
    private String name;

    @ManyToOne(cascade={CascadeType.ALL})
    @JoinColumn(name="manager_id")
    private Account manager;

    @OneToMany((fetch = FetchType.EAGER, mappedBy="manager")
    private Set<Account> linkedAccounts = new HashSet<Account>();

}

Answer 5

As user1819111 told, @Data from Lombok is not compatible with @Entity and FetchType=LAZY. I had used Lombok.Data (@Data) and I was getting this error.

As I don't want do create all get/set, I just put the Lombok @Setter and @Getter in your class and all will work fine.

@Setter
@Getter
@Entity
@Table(name = "file")
@SequenceGenerator(name = "File_Sequence", allocationSize=1, sequenceName = "file_id_seq")
public class MyClass{
    @Id
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "File_Sequence")
    @Column(name = "id")
    private Long id;

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

    @OneToMany(mappedBy = "file", cascade = CascadeType.DETACH, fetch = FetchType.LAZY)
    private Set<Base2FileDetail> details = new HashSet<>();
}