Explain features of Spring Data JPA?

Spring Data JPA offers a set of features designed to eliminate repetitive data-access boilerplate, including automatic repository implementation, query generation from method names, built-in pagination and sorting, and support for both derived and custom queries.

Key Points: • Automatic repository creation: extending an interface like JpaRepository gives you a fully working implementation with no manual coding. • Query method generation: method names like findByLastName are parsed into real queries automatically. • Pagination and sorting: Pageable and Sort parameters let you page and order results without manual LIMIT/OFFSET or ORDER BY logic. • Custom queries: @Query supports JPQL and native SQL for cases derivation can't cover. • Auditing support: annotations like @CreatedDate and @LastModifiedDate can automatically populate timestamp fields. • Seamless integration with Spring Boot and other Spring projects, requiring minimal configuration to get a working data layer.

Example: A single ProductRepository interface extending JpaRepository can offer full CRUD, a derived findByCategoryAndPriceLessThan() search method, paginated results via a Pageable parameter, and a custom @Query for a complex report, all without writing a DAO implementation class.

Code Example:

public interface ProductRepository extends JpaRepository<Product, Long> {
    Page<Product> findByCategory(String category, Pageable pageable);
    List<Product> findByPriceLessThan(BigDecimal price);

    @Query("SELECT p FROM Product p WHERE p.stock = 0")
    List<Product> findOutOfStock();
}

Interview Tip: A concise interview answer is:

"Spring Data JPA's core features are automatic repository implementations, query generation from method names, built-in pagination and sorting through Pageable, custom JPQL/native queries via @Query, and auditing support for timestamp fields. Together they mean I can build a full data access layer with almost no boilerplate implementation code."