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
  @GeneratedValue
  private long id;
  private String name;

  @OneToMany(fetch = FetchType.EAGER, mappedBy = "parentAccount")
  private Set<LinkedAccount> linkedAccounts;

}

child:

@Entity
public class LinkedAccount {

  @Id
  @GeneratedValue
  private long id;

  @ManyToOne(optional = false)
  private ParentAccount parentAccount;

  private String name;

  // empty constructor for JPA
  public LinkedAccount() {
  }

}

I ma using Spring CrudRepository to operate with these entities. However, when calling ParentAccount parent = parentAccountRepository.findOne(id);, some kind of infinite loop starts happening and hibernate spams this all over the console:

Hibernate: select linkedacco0_.parent_account_id as parent_a6_1_0_, linkedacco0_.id as id1_0_0_, linkedacco0_.id as id1_0_1_, linkedacco0_.aws_id as aws_id2_0_1_, linkedacco0_.key_id as key_id3_0_1_, linkedacco0_.name as name4_0_1_, linkedacco0_.parent_account_id as parent_a6_0_1_, linkedacco0_.secret_key as secret_k5_0_1_ from linked_account linkedacco0_ where linkedacco0_.parent_account_id=?

I tried changed the fetch type to LAZY but then I get this error:

org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: com.berrycloud.scheduler.model.ParentAccount.linkedAccounts, could not initialize proxy - no Session

(It seems that it is trying to do the lazy load outside of the transactional context).

This is my CRUD repository:

@Repository
public interface ParentAccountRepository extends CrudRepository<ParentAccount, Long> {
}

Could someone tell me how to resolve this issue? I would prefer the solution with EAGER fetch. Thank you for any tips

EDIT: here is the schema I am using

CREATE TABLE parent_account (
    id BIGINT auto_increment,
    name VARCHAR(80) null,
    PRIMARY KEY (`id`)
);

CREATE TABLE linked_account (
    id BIGINT auto_increment,
    parent_account_id BIGINT,
    name VARCHAR(80) null,
    FOREIGN KEY (`parent_account_id`) REFERENCES `parent_account` (`id`),
    PRIMARY KEY (`id`)
);

Answer 1

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 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.