Polish "Lazily resolve JPA fallback bootstrap executor"

See gh-50801

module/spring-boot-hibernate/src/test/java/org/springframework/boot/hibernate/autoconfigure/HibernateJpaAutoConfigurationTests.java

@@ -104,6 +104,7 @@ import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.Primary;
 import org.springframework.context.event.ContextRefreshedEvent;
+import org.springframework.core.task.AsyncTaskExecutor;
 import org.springframework.core.task.SimpleAsyncTaskExecutor;
 import org.springframework.jdbc.core.JdbcTemplate;
 import org.springframework.jdbc.support.SQLExceptionTranslator;
@@ -304,11 +305,11 @@ class HibernateJpaAutoConfigurationTests {
 	}
 
 	@Test
-	void whenAsyncTaskExecutorIsDefinedInJpaDependentConfigurationDoesNotTriggerABeanCurrentlyInCreationException() {
-		this.contextRunner.withUserConfiguration(AsyncTaskExecutorDependingOnEntityManagerFactoryConfiguration.class)
+	void whenAsyncTaskExecutorIsDefinedInJpaDependentConfigurationDoesNotFail() {
+		this.contextRunner.withUserConfiguration(TaskExecutorDependingOnEntityManagerFactoryConfiguration.class)
 			.run((context) -> {
 				assertThat(context).hasNotFailed();
-				assertThat(context).hasSingleBean(EntityManagerFactory.class);
+				assertThat(context).hasSingleBean(EntityManagerFactory.class).hasSingleBean(AsyncTaskExecutor.class);
 			});
 	}
 
@@ -1484,9 +1485,9 @@ class HibernateJpaAutoConfigurationTests {
 	}
 
 	@Configuration(proxyBeanMethods = false)
-	static class AsyncTaskExecutorDependingOnEntityManagerFactoryConfiguration {
+	static class TaskExecutorDependingOnEntityManagerFactoryConfiguration {
 
-		AsyncTaskExecutorDependingOnEntityManagerFactoryConfiguration(EntityManagerFactory entityManagerFactory) {
+		TaskExecutorDependingOnEntityManagerFactoryConfiguration(EntityManagerFactory entityManagerFactory) {
 		}
 
 		@Bean

module/spring-boot-jpa/src/main/java/org/springframework/boot/jpa/EntityManagerFactoryBuilder.java

@@ -121,7 +121,10 @@ public class EntityManagerFactoryBuilder {
 	 * @param fallbackBootstrapExecutor the fallback executor to use when background
 	 * bootstrapping is required but no explicit executor has been set
 	 * @since 4.1.0
+	 * @deprecated since 4.1.1 for removal in 4.3.0 in favor of
+	 * {@link #EntityManagerFactoryBuilder(JpaVendorAdapter, Function, PersistenceUnitManager, URL, Supplier)}
 	 */
+	@Deprecated(since = "4.1.1", forRemoval = true)
 	public EntityManagerFactoryBuilder(JpaVendorAdapter jpaVendorAdapter,
 			Function<DataSource, Map<String, ?>> jpaPropertiesFactory,
 			@Nullable PersistenceUnitManager persistenceUnitManager, @Nullable URL persistenceUnitRootLocation,
@@ -141,8 +144,7 @@ public class EntityManagerFactoryBuilder {
 	 * @param persistenceUnitRootLocation the persistence unit root location to use as a
 	 * fallback or {@code null}
 	 * @param fallbackBootstrapExecutor a supplier of the fallback executor to use when
-	 * background bootstrapping is required but no explicit executor has been set. The
-	 * supplier is only invoked when background bootstrapping is actually required.
+	 * background bootstrapping is required, but no explicit executor has been set.
 	 * @since 4.1.1
 	 */
 	public EntityManagerFactoryBuilder(JpaVendorAdapter jpaVendorAdapter,

module/spring-boot-jpa/src/test/java/org/springframework/boot/jpa/EntityManagerFactoryBuilderTests.java

@@ -104,7 +104,7 @@ class EntityManagerFactoryBuilderTests {
 
 	@Test
 	void requireBootstrapExecutorWhenFallbackExecutorProvidesExecutorDoesNotThrow() {
-		EntityManagerFactoryBuilder builder = createEmptyBuilder(new SimpleAsyncTaskExecutor());
+		EntityManagerFactoryBuilder builder = createEmptyBuilder(SimpleAsyncTaskExecutor::new);
 		builder.requireBootstrapExecutor(() -> new IllegalStateException("BAD"));
 		DataSource dataSource = mock();
 		assertThatNoException().isThrownBy(builder.dataSource(dataSource)::build);
@@ -129,7 +129,7 @@ class EntityManagerFactoryBuilderTests {
 
 	@Test
 	void requireBootstrapExecutorWhenFallbackExecutorSupplierProvidesExecutorDoesNotThrow() {
-		EntityManagerFactoryBuilder builder = createEmptyBuilderWithFallbackSupplier(SimpleAsyncTaskExecutor::new);
+		EntityManagerFactoryBuilder builder = createEmptyBuilder(SimpleAsyncTaskExecutor::new);
 		builder.requireBootstrapExecutor(() -> new IllegalStateException("BAD"));
 		DataSource dataSource = mock();
 		assertThatNoException().isThrownBy(builder.dataSource(dataSource)::build);
@@ -138,7 +138,7 @@ class EntityManagerFactoryBuilderTests {
 	@Test
 	void fallbackExecutorSupplierIsNotInvokedWhenBootstrapExecutorNotRequired() {
 		AtomicBoolean invoked = new AtomicBoolean();
-		EntityManagerFactoryBuilder builder = createEmptyBuilderWithFallbackSupplier(() -> {
+		EntityManagerFactoryBuilder builder = createEmptyBuilder(() -> {
 			invoked.set(true);
 			return new SimpleAsyncTaskExecutor();
 		});
@@ -148,16 +148,10 @@ class EntityManagerFactoryBuilderTests {
 	}
 
 	private EntityManagerFactoryBuilder createEmptyBuilder() {
-		return createEmptyBuilder(null);
+		return createEmptyBuilder(() -> null);
 	}
 
-	private EntityManagerFactoryBuilder createEmptyBuilder(@Nullable AsyncTaskExecutor fallbackBootstrapExecutor) {
-		Function<DataSource, Map<String, ?>> jpaPropertiesFactory = (dataSource) -> Collections.emptyMap();
-		return new EntityManagerFactoryBuilder(new TestJpaVendorAdapter(), jpaPropertiesFactory, null, null,
-				fallbackBootstrapExecutor);
-	}
-
-	private EntityManagerFactoryBuilder createEmptyBuilderWithFallbackSupplier(
+	private EntityManagerFactoryBuilder createEmptyBuilder(
 			Supplier<? extends @Nullable AsyncTaskExecutor> fallbackBootstrapExecutorSupplier) {
 		Function<DataSource, Map<String, ?>> jpaPropertiesFactory = (dataSource) -> Collections.emptyMap();
 		return new EntityManagerFactoryBuilder(new TestJpaVendorAdapter(), jpaPropertiesFactory, null, null,