Spring Data JPA: Child 'deleteById' is reverted by parent 'findById'

Hibernate ORM
1

Hello

I will appreciate if someone explain me behavior of my code

I have parent-child , one-to-one relation

@Entity
public class Country {

    @Id @GeneratedValue
    private Long id;

    private String name;

    @OneToOne(mappedBy = "country", cascade =  CascadeType.ALL)
    private City capital;

---

@Entity
public class City {

    @Id @GeneratedValue
    private Long id;

    private String name;

    @OneToOne(fetch = FetchType.LAZY)
    private Country country;

My test code (Spring Data JPA) is:

new TransactionTemplate(transactionManager).execute(s -> {

  cityRepository.deleteById(parisId);
  //countryRepository.findById(franceId);
  return "ok";
});

System.out.println("Transaction completed");
Country country  = countryRepository.findById(franceId).orElseThrow(() -> ...);
System.out.println("Country " + country + " capital: " + country.getCapital());

This version prints

Country 1:France capital: null

And that is something I expect
But if I uncomment //countryRepository.findById(franceId)
I got this:

Country 1:France capital: 2:Paris

That is something I do not expect.

Why select (findById) reverts delete (deleteById)?
What is proper Hibernate usage to avoid that trap?

2

In the meantime I found answer for first question.
It is case known as un-scheduling entity deletion - there are several posts SO explaining that