JpaRepository vs CrudRepository vs PagingAndSortingRepository.

These interfaces form an inheritance chain, and each one adds a layer of capability — JpaRepository is the bottom and gives you everything. Knowing the order shows you understand that you can pick the narrowest interface that exposes only what callers should use.

The hierarchy

Repository<T, ID>                  // marker, no methods
  └─ CrudRepository<T, ID>         // save, findById, findAll, delete, count, existsById
       ├─ ListCrudRepository<T,ID> // same but returns List instead of Iterable
       └─ PagingAndSortingRepository<T, ID>   // findAll(Pageable), findAll(Sort)
            └─ ListPagingAndSortingRepository<T, ID>
  └─ JpaRepository<T, ID>          // extends ListCrud + ListPagingAndSorting + flush, saveAndFlush,
                                   //   deleteAllInBatch, getReferenceById, JPA-specific extras

Repository is an empty marker interface — it just tells Spring Data "manage this." CrudRepository adds the basic CRUD operations but returns Iterable<T> from findAll. ListCrudRepository (Spring Data 3.x) returns List<T>, which is almost always what you want. PagingAndSortingRepository adds findAll(Pageable) and findAll(Sort) — note it does not extend CrudRepository, so on its own it only does paging.

JpaRepository — the JPA-specific one

public interface OrderRepository extends JpaRepository<Order, Long> { }

JpaRepository combines ListCrudRepository and ListPagingAndSortingRepository and adds JPA-flavoured methods: flush(), saveAndFlush(), deleteAllInBatch(), and getReferenceById() (returns a lazy proxy via EntityManager.getReference, no SELECT until you touch it). This is the interface most teams extend by default.

Why ever pick a narrower one?

Two reasons. First, API hygiene — if a repository should never be paged, extend CrudRepository so callers can't reach for Pageable. Second, portability — CrudRepository and PagingAndSortingRepository are store-agnostic (they live in Spring Data Commons), so the same interface works for Mongo, Redis, etc. JpaRepository ties you to JPA. In practice most JPA projects extend JpaRepository and don't worry about it.