JPA - OneToMany struggle

Question

I have an entity Property which has several PropertyAttributes - managed as list, i.e.

@OneToMany(mappedBy = "property", cascade = { CascadeType.ALL}, fetch = FetchType.EAGER)
@JoinFetch(value = JoinFetchType.INNER)
private List<PropertyAttribute> propertyAttribute;

in the PropertyAttribute I have as well a reference to the Property, i.e.

@Id
@JsonIgnore
@JoinColumn(name = "property_id")
@ManyToOne
private Property property; 

when I save a new Property,e.g. id=10400 than the additional PropertyAttribute is saved as well with the same id - as expected. My save() method looks like:

public void save(){
   //begin transaction
   getEntityManager.persist(newProperty);
   // end transaction...
   //begin transaction...
   getEntityManager.merge(newPropertyAttriubtes);
   // end transaction
}

But when I perform the second round of save() (now with id=10401 then I get strange results, namely:

getEntityManager().find(Property.class,10400)

has now PropertyAttribute with Property - id = 10401, i.e. from the last saved record (=wrong content!)

Any ideas why it fails with the second save? Might it be a DB-issue? Or EclipseLink?

Answer 1

I finally figured out how to do it properly :-/ Just in case others struggle the same...

public void save(){
   //begin transaction
   getEntityManager.persist(newProperty);
   // end transaction...
   newPropertyAttriubtes.forEach(attr -> {
          //begin transaction...
          getEntityManager.merge(attr);
          // end transaction
          newProperty.attach(attr)
   }
   //begin transaction
   // to have the PropertyAttributes attached in the EntityManager => merge
   getEntityManager.merge(newProperty); 
   // end transaction...
   }
}

Thx for Chris to point me to the correct direction to not change the Entity after JPA manage it!