FetchType.LAZY is working as FetchType.EAGER - spring

Question

I have a problem with hibernate, namely with lazy data fetching. I have two entities and one of them clinic is having relation #OneToMany. I setup FetchType to LAZY, but still, when I am making request to get all clinic, I still have an array in the clinic entity. The questions is - why I am still getting full #OneToMany array? Shouldn't it be null?
Here I provided my entity classes
#Getter
#Setter
#Entity(name = "clinic")
public class Clinic {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String name;
#OneToMany(fetch = FetchType.LAZY, mappedBy="clinic")
private List<Doctor> doctors;
}
And doctor entity
#Getter
#Setter
#Entity(name = "doctor")
public class Doctor {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String firstname;
private String lastname;
#ManyToOne(fetch = FetchType.LAZY)
#JsonIgnore
private Clinic clinic;
}
And my controller, which is JpaRepository interface
#RestController
#RequestMapping("clinics")
public class ClinicController {
private final ClinicRepository clinicRepository;
public ClinicController(ClinicRepository clinicRepository) {this.clinicRepository = clinicRepository;}
#GetMapping()
public List<Clinic> getAllClinics() {
return clinicRepository.findAll();
}
}
I also logged SQL provided by Hibernate and it looks like this
Hibernate: select clinic0_.id as id1_0_, clinic0_.name as name2_0_ from clinic clinic0_
Hibernate: select doctors0_.clinic_id as clinic_i4_1_0_, doctors0_.id as id1_1_0_, doctors0_.id as id1_1_1_, doctors0_.clinic_id as clinic_i4_1_1_, doctors0_.firstname as firstnam2_1_1_, doctors0_.lastname as lastname3_1_1_ from doctor doctors0_ where doctors0_.clinic_id=?
Hibernate: select doctors0_.clinic_id as clinic_i4_1_0_, doctors0_.id as id1_1_0_, doctors0_.id as id1_1_1_, doctors0_.clinic_id as clinic_i4_1_1_, doctors0_.firstname as firstnam2_1_1_, doctors0_.lastname as lastname3_1_1_ from doctor doctors0_ where doctors0_.clinic_id=?
As I understand, it supposed to send only one query (first select).
And of course, I also will provide an answer that I am getting right now
[
{
"id": 1,
"name": "Clinic 1",
"doctors": [
{
"id": 1,
"firstname": "Bob",
"lastname": "Fisher"
},
{
"id": 2,
"firstname": "John",
"lastname": "Cena"
}
]
},
{
"id": 2,
"name": "Clinic 2",
"doctors": [
{
"id": 3,
"firstname": "Some",
"lastname": "guy"
}
]
}
]

Answer 1

The association is lazily loaded because Jackson (JSON serialization library) simply serializes this proxy collection. Lazy loading is possible because Spring enables the open-session-in-view by default. If you turn that config off, you will see a LazyInitializationException.
What you want though, is to tell Jackson not to serialize the collection, by annotating it with #JsonIgnore:
#JsonIgnore
#OneToMany(fetch = FetchType.LAZY, mappedBy="clinic")
private List<Doctor> doctors;