Spring Boot Data Persistence with JPA Questions and Answers

Question 1

A developer is implementing a repository for a `Product` entity and needs basic CRUD operations as well as JPA-specific functionalities like flushing the persistence context and batch deletes.
Which Spring Data interface is the most appropriate to extend for this use case?

Accepted Answer

JpaRepository

Answer

PagingAndSortingRepository

Answer

CrudRepository

Answer

Repository

Question 2

In a Spring Boot application, a developer needs to execute a database-specific SQL query that uses a function not supported by JPQL. Which annotation and attribute should be used on the repository method to achieve this?

Accepted Answer

@Query(nativeQuery = true)

Answer

@NativeQuery

Answer

@Query(value = "...", type = "native")

Answer

@Sql

Question 3

A `Post` entity has a one-to-many relationship with a `Comment` entity. The developer wants to ensure that whenever a `Post` is deleted, all of its associated `Comment` entities are also automatically deleted from the database. Which `CascadeType` should be configured on the relationship?

Accepted Answer

CascadeType.REMOVE

Answer

CascadeType.MERGE

Answer

CascadeType.PERSIST

Answer

CascadeType.ALL

Question 4

A developer observes that when they load a `Department` entity, all of its associated `Employee` entities are also loaded from the database immediately, causing performance issues due to the large number of employees. What is the most likely cause of this behavior?

Accepted Answer

The relationship is explicitly marked with `fetch = FetchType.EAGER`.

Answer

The relationship is explicitly marked with `fetch = FetchType.LAZY`.

Answer

A `LazyInitializationException` is being thrown and caught silently.

Answer

The `@Transactional` annotation is missing from the service method.

Question 5

A service method, annotated with `@Transactional`, calls another public method within the same class that is also annotated with `@Transactional(propagation = Propagation.REQUIRES_NEW)`. What is the expected transactional behavior when the inner method is invoked?

Accepted Answer

The call will not be transactional because self-invocation is not proxied by default.

Answer

The inner method will participate in the existing transaction of the outer method.

Answer

A `NestedTransactionNotSupportedException` will be thrown.

Answer

The outer method's transaction will be suspended, and a new, independent transaction will be created for the inner method.

Question 6

Which JPA lifecycle callback annotation should be used on a method within an entity to automatically set a `lastModifiedDate` field to the current time just before an existing entity is updated in the database?

Accepted Answer

@PreUpdate

Answer

@PostUpdate

Answer

@PrePersist

Answer

@PostLoad