Detached entity passed to persist Error in spring jpa With Scheduler threads

Question

i have getting this exception when i try to save and flush Object From Class A. (spring version 2.7.8)

@Table(name= "table_a")
@Entity
@Data
public class A {
@Id
@GeneratedValue(strategy=GenerationType.IDENTITY)
private Long id;

@ManyToOne(optional = false, targetEntity = B.class, cascade = CascadeType.PERSIST)
private B b;
//...etc
}

and class B:

@Table(name= "table_b")
@Entity
@Data
public class B {
@Id
@GeneratedValue(strategy=GenerationType.IDENTITY)
private Long id;
//...etc
}

my code block:

public void saveData(A a){
aJpaRepository.saveAndFlush(a);
}


when saveData invoked from Api Call Request its work and cascaded correctly, but when I call it with same object from scheduler thread it occurred this exception:

org.springframework.dao.InvalidDataAccessApiUsageException: detached entity passed to persist: com.example.model.B; nested exception is org.hibernate.PersistentObjectException: detached entity passed to persist: com.example.model.B
    at org.springframework.orm.jpa.vendor.HibernateJpaDialect.convertHibernateAccessException(HibernateJpaDialect.java:297)

solution and explaining for this behavior?

crizzis · Accepted Answer · 2024-08-06 18:29:03Z

0

Transactions (and by extension, JPA units of work) are thread local in Spring. They do not propagate across different threads.

This means when you're trying to save the entity from a separate thread, it is seen as detached. You have to make sure you have Cascade.MERGE declared on the association from A to B.

Even with this issue fixed, remember that there is no transaction spanning both threads, which may affect the correctness of your business logic.

answered Aug 6, 2024 at 18:29

crizzis

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1 Comment

O.Zaytoon Over a year ago

thanks a lot, i have add merge to cascade type but unfortunately, same issue occurred. but your answer lead me to the solution so thanks a lot

O.Zaytoon · Accepted Answer · 2024-08-07 05:27:55Z

0

The solution was by add the following block of code:

@PersistenceContext
private EntityManager entityManager;

@Transactional
public A saveA(A a) {
  a.setB(entityManager.merge(a.getB));
  return aJpaRepostiory.saveAndFlush(a);
}

Thanks for your help

answered Aug 7, 2024 at 5:27

O.Zaytoon

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