Adds JpaRepository.getById, deprecats JpaRepository.getOne

This makes the method names  in JpaRepository consistent with the names in CrudRepository.

Closes #1697
Original pull request #2169

Author: JesseW28

src/main/java/org/springframework/data/jpa/repository/JpaRepository.java

@@ -32,6 +32,7 @@
  * @author Christoph Strobl
  * @author Mark Paluch
  * @author Sander Krabbenborg
+ * @author Jesse Wouters
  */
 @NoRepositoryBean
 public interface JpaRepository<T, ID> extends PagingAndSortingRepository<T, ID>, QueryByExampleExecutor<T> {
@@ -131,9 +132,23 @@ public interface JpaRepository<T, ID> extends PagingAndSortingRepository<T, ID>,
 	 * @param id must not be {@literal null}.
 	 * @return a reference to the entity with the given identifier.
 	 * @see EntityManager#getReference(Class, Object) for details on when an exception is thrown.
+	 * @deprecated use {@link JpaRepository#getById(ID)} instead.
 	 */
+	@Deprecated
 	T getOne(ID id);
 
+	/**
+	 * Returns a reference to the entity with the given identifier. Depending on how the JPA persistence provider is
+	 * implemented this is very likely to always return an instance and throw an
+	 * {@link javax.persistence.EntityNotFoundException} on first access. Some of them will reject invalid identifiers
+	 * immediately.
+	 *
+	 * @param id must not be {@literal null}.
+	 * @return a reference to the entity with the given identifier.
+	 * @see EntityManager#getReference(Class, Object) for details on when an exception is thrown.
+	 */
+	T getById(ID id);
+
 	/*
 	 * (non-Javadoc)
 	 * @see org.springframework.data.repository.query.QueryByExampleExecutor#findAll(org.springframework.data.domain.Example)

src/main/java/org/springframework/data/jpa/repository/support/SimpleJpaRepository.java

@@ -74,6 +74,7 @@
  * @author David Madden
  * @author Moritz Becker
  * @author Sander Krabbenborg
+ * @author Jesse Wouters
  * @param <T> the type of the entity to handle
  * @param <ID> the type of the entity's identifier
  */
@@ -323,13 +324,25 @@ protected QueryHints getQueryHints() {
 	 * (non-Javadoc)
 	 * @see org.springframework.data.jpa.repository.JpaRepository#getOne(java.io.Serializable)
 	 */
+	@Deprecated
 	@Override
 	public T getOne(ID id) {
 
 		Assert.notNull(id, ID_MUST_NOT_BE_NULL);
 		return em.getReference(getDomainClass(), id);
 	}
 
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.jpa.repository.JpaRepository#getById(java.io.Serializable)
+	 */
+	@Override
+	public T getById(ID id) {
+
+		Assert.notNull(id, ID_MUST_NOT_BE_NULL);
+		return em.getReference(getDomainClass(), id);
+	}
+
 	/*
 	 * (non-Javadoc)
 	 * @see org.springframework.data.repository.CrudRepository#existsById(java.io.Serializable)

src/test/java/org/springframework/data/jpa/repository/AbstractPersistableIntegrationTests.java

@@ -36,6 +36,7 @@
  * @author Thomas Darimont
  * @author Oliver Gierke
  * @author Jens Schauder
+ * @author Jesse Wouters
  */
 @Transactional
 @ExtendWith(SpringExtension.class)
@@ -66,4 +67,16 @@ void equalsWorksForProxiedEntities() {
 
 		assertThat(proxy).isEqualTo(proxy);
 	}
+
+	@Test // gh-1697
+	void equalsWorksForProxiedEntitiesUsingGetById() {
+
+		CustomAbstractPersistable entity = repository.saveAndFlush(new CustomAbstractPersistable());
+
+		em.clear();
+
+		CustomAbstractPersistable proxy = repository.getById(entity.getId());
+
+		assertThat(proxy).isEqualTo(proxy);
+	}
 }

src/test/java/org/springframework/data/jpa/repository/UserRepositoryTests.java

@@ -91,6 +91,7 @@
  * @author Jens Schauder
  * @author Andrey Kovalev
  * @author Sander Krabbenborg
+ * @author Jesse Wouters
  */
 @ExtendWith(SpringExtension.class)
 @ContextConfiguration("classpath:application-context.xml")
@@ -999,6 +1000,15 @@ void looksUpEntityReference() {
 		assertThat(result).isEqualTo(firstUser);
 	}
 
+	@Test // gh-1697
+	void looksUpEntityReferenceUsingGetById() {
+
+		flushTestUsers();
+
+		User result = repository.getById(firstUser.getId());
+		assertThat(result).isEqualTo(firstUser);
+	}
+
 	@Test // DATAJPA-415
 	void invokesQueryWithVarargsParametersCorrectly() {