Cascade types and behavior in Spring Boot - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ component_behavior

intermediate

What happens when you delete a parent entity with CascadeType.REMOVE?

Consider a parent entity with a one-to-many relationship to child entities using CascadeType.REMOVE. What is the behavior when the parent entity is deleted?

Spring Boot

public class Parent {
  @OneToMany(cascade = CascadeType.REMOVE)
  private List<Child> children;
}

// Deleting a Parent instance

A Child entities are detached but not deleted; they remain unmanaged.

B Only the parent entity is deleted; child entities remain in the database.

C Deleting the parent causes an error because child entities must be deleted first manually.

D Both the parent and all its child entities are deleted from the database.

💡 Hint

Think about what CascadeType.REMOVE means for related entities.

CascadeType.REMOVE causes the persistence provider to delete all related child entities automatically when the parent is deleted.

❓ state_output

intermediate

What is the state of child entities after persisting a parent with CascadeType.PERSIST?

Given a parent entity with a one-to-many relationship to children using CascadeType.PERSIST, what happens to the child entities when the parent is saved for the first time?

Spring Boot

public class Parent {
  @OneToMany(cascade = CascadeType.PERSIST)
  private List<Child> children;
}

Parent parent = new Parent();
parent.getChildren().add(new Child());
entityManager.persist(parent);

A Only the parent is saved; child entities remain transient and are not saved.

B Both parent and child entities are saved to the database in the same transaction.

C Child entities are saved but parent remains transient.

D Saving the parent causes an exception because children are not explicitly saved.

💡 Hint

CascadeType.PERSIST propagates the persist operation to children.

CascadeType.PERSIST ensures that when the parent is persisted, all new child entities are also persisted automatically.

📝 Syntax

advanced

Which option correctly applies multiple cascade types to a relationship?

You want to apply both PERSIST and MERGE cascade types to a one-to-one relationship. Which code snippet is correct?

Spring Boot

public class User {
  @OneToOne(cascade = ???)
  private Profile profile;
}

A cascade = CascadeType.PERSIST, CascadeType.MERGE

B cascade = [CascadeType.PERSIST, CascadeType.MERGE]

C cascade = {CascadeType.PERSIST, CascadeType.MERGE}

D cascade = (CascadeType.PERSIST, CascadeType.MERGE)

💡 Hint

Look for the correct Java syntax for arrays in annotations.

The cascade attribute expects an array of CascadeType enums enclosed in curly braces {}.

🔧 Debug

advanced

Why does deleting a parent entity not delete child entities despite CascadeType.ALL?

Given this code, deleting the parent does not remove child entities. What is the likely cause? public class Parent { @OneToMany(cascade = CascadeType.ALL) private List children; } entityManager.remove(parent);

A The orphanRemoval attribute is not set to true, so children are not deleted when removed from parent.

B CascadeType.ALL does not include REMOVE, so children are not deleted.

C The parent entity is not managed, so remove does nothing.

D The children collection is empty, so nothing happens.

💡 Hint

CascadeType.ALL includes REMOVE, but deleting orphans requires a separate setting.

CascadeType.ALL includes REMOVE, but to delete child entities removed from the parent's collection, orphanRemoval=true must be set.

🧠 Conceptual

expert

Which cascade type should you avoid on a ManyToMany relationship to prevent unintended deletions?

In a ManyToMany relationship, which cascade type can cause dangerous side effects by deleting shared entities unintentionally?

A CascadeType.REMOVE

B CascadeType.MERGE

C CascadeType.PERSIST

D CascadeType.REFRESH

💡 Hint

Think about what happens if you delete one side of a shared relationship.

CascadeType.REMOVE on ManyToMany can delete entities shared by multiple parents, causing data loss.