How is jackson serializing object outside of transition - spring-boot

Question

This is a bit bizarre for me. My understanding is if you try to access entity outside of Hibernate session you should get an LazyInitializationException - no session, but I am not getting this exception. In fact it seems like I still have session continue to my controller outside of my service layer which has #Transactional annotation.
Question
Is this the way it should be? or there is something I didn't set up correctly?
Structure
User
|
Profile { hierarchies entity }
|
+-----+-----+
| |
Teacher Student
User
#Entity
#Table(name="user")
public class User {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String firstname;
private String lastname;
#OneToMany(fetch = FetchType.LAZY , mappedBy = "user")
#JsonManagedReference
#JsonInclude(JsonInclude.Include.NON_EMPTY)
private List<Profile> profiles = new ArrayList<>();
Service
#Override
#Transactional
public User getUserById(Long id) {
Optional<User> optionalUser = userRepo.findById(id);
User user = optionalUser.get();
logger.info("\n User -> {}", user);
return user;
}
Controller :: Instead of thow Exception, or should return empty array. Hibernate perform a left join
#GetMapping(value="/{userId}", produces=MediaType.APPLICATION_JSON_UTF8_VALUE)
public User getUser(#PathVariable("userId") Long userId) {
logger.info("User Controller is called");
User user = userService.getUserById(userId);
logger.info("User is returned -> {}", user);
logger.info("Profiles -> {}", user.getProfiles()); // <-- Expecting this to throw LazyInitializationException
return user;
}
Console
018-05-31 15:17:35.462 INFO 15599 --- [nio-8080-exec-1] c.d.c.controller.UserController : User Controller is called
Hibernate:
select
user0_.id as id1_4_0_,
user0_.firstname as firstnam2_4_0_,
user0_.lastname as lastname3_4_0_
from
user user0_
where
user0_.id=?
2018-05-31 15:17:35.467 INFO 15599 --- [nio-8080-exec-1] c.d.c.services.UserServiceImpl :
User ->
User [id=1, firstname=Hendric, lastname=Rosenberg]
2018-05-31 15:17:35.467 INFO 15599 --- [nio-8080-exec-1] c.d.c.controller.UserController : User is returned ->
User [id=1, firstname=Hendric, lastname=Rosenberg]
Hibernate:
select
profiles0_.user_id as user_id2_3_0_,
profiles0_.id as id1_3_0_,
profiles0_.id as id1_3_1_,
profiles0_.user_id as user_id2_3_1_,
profiles0_1_.citizent_id as citizent1_2_1_,
profiles0_1_.profile_type as profile_2_2_1_,
profiles0_2_.license as license1_1_1_,
profiles0_2_.practitioner_type as practiti2_1_1_,
profiles0_2_.profile_type as profile_3_1_1_,
profiles0_2_.specialized as speciali4_1_1_,
case
when profiles0_1_.id is not null then 1
when profiles0_2_.id is not null then 2
when profiles0_.id is not null then 0
end as clazz_1_
from
profile profiles0_
left outer join
patient profiles0_1_
on profiles0_.id=profiles0_1_.id
left outer join
medical_profession profiles0_2_
on profiles0_.id=profiles0_2_.id
where
profiles0_.user_id=?
c.d.c.controller.UserController : User is returned -> [
Student [profileType=STUDENT, id=A1236578889],
Teacher [profileType=TEACHER, license=234SFLLWEKD32342]]

Answer 1

spring.jpa.open-in-view = true is set by default. So you won't get a LazyInitializationException
This property will register an OpenEntityManagerInViewInterceptor
Spring web request interceptor that binds a JPA EntityManager to the thread for the entire processing of the request. Intended for the "Open EntityManager in View" pattern, i.e. to allow for lazy loading in web views despite the original transactions already being completed.
This interceptor makes JPA EntityManagers available via the current thread, which will be autodetected by transaction managers. It is suitable for service layer transactions via JpaTransactionManager or JtaTransactionManager as well as for non-transactional read-only execution.
In contrast to OpenEntityManagerInViewFilter, this interceptor is set up in a Spring application context and can thus take advantage of bean wiring.