Change default BootstrapMode for JPA repositories

Change the default `BootstrapMode` for auto-configured `JpaRepositories`
to `BootstrapMode.DEFERRED` to allow the initialization of
`EntityManagerFactory` to be parallelized for increased startup efficiency.

Prior to this change, the default BootstrapMode for all auto-configured
Spring Data repositories was `BootstrapMode.DEFAULT`.

Closes gh-16230

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/data/jpa/JpaRepositoriesAutoConfiguration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -56,6 +56,7 @@ import org.springframework.data.jpa.repository.support.JpaRepositoryFactoryBean;
  *
  * @author Phillip Webb
  * @author Josh Long
+ * @author Scott Frederick
  * @since 1.0.0
  * @see EnableJpaRepositories
  */
@@ -95,7 +96,7 @@ public class JpaRepositoriesAutoConfiguration {
 		}
 
 		@ConditionalOnProperty(prefix = "spring.data.jpa.repositories", name = "bootstrap-mode",
-				havingValue = "deferred", matchIfMissing = false)
+				havingValue = "deferred", matchIfMissing = true)
 		static class DeferredBootstrapMode {
 
 		}

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/data/jpa/JpaRepositoriesRegistrar.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -34,6 +34,7 @@ import org.springframework.util.StringUtils;
  *
  * @author Phillip Webb
  * @author Dave Syer
+ * @author Scott Frederick
  */
 class JpaRepositoriesRegistrar extends AbstractRepositoryConfigurationSourceSupport {
 
@@ -56,7 +57,7 @@ class JpaRepositoriesRegistrar extends AbstractRepositoryConfigurationSourceSupp
 
 	@Override
 	protected BootstrapMode getBootstrapMode() {
-		return (this.bootstrapMode == null) ? super.getBootstrapMode() : this.bootstrapMode;
+		return (this.bootstrapMode == null) ? BootstrapMode.DEFERRED : this.bootstrapMode;
 	}
 
 	@Override

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/data/jpa/JpaRepositoriesAutoConfigurationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -51,6 +51,7 @@ import static org.assertj.core.api.Assertions.assertThat;
  *
  * @author Dave Syer
  * @author Oliver Gierke
+ * @author Scott Frederick
  */
 class JpaRepositoriesAutoConfigurationTests {
 
@@ -85,7 +86,7 @@ class JpaRepositoriesAutoConfigurationTests {
 	}
 
 	@Test
-	void whenBootstrappingModeIsLazyWithMultipleAsyncExecutorBootstrapExecutorIsConfigured() {
+	void whenBootstrapModeIsLazyWithMultipleAsyncExecutorBootstrapExecutorIsConfigured() {
 		this.contextRunner.withUserConfiguration(MultipleAsyncTaskExecutorConfiguration.class)
 				.withConfiguration(AutoConfigurations.of(TaskExecutionAutoConfiguration.class,
 						TaskSchedulingAutoConfiguration.class))
@@ -96,7 +97,7 @@ class JpaRepositoriesAutoConfigurationTests {
 	}
 
 	@Test
-	void whenBootstrappingModeIsLazyWithSingleAsyncExecutorBootstrapExecutorIsConfigured() {
+	void whenBootstrapModeIsLazyWithSingleAsyncExecutorBootstrapExecutorIsConfigured() {
 		this.contextRunner.withUserConfiguration(SingleAsyncTaskExecutorConfiguration.class)
 				.withPropertyValues("spring.data.jpa.repositories.bootstrap-mode=lazy")
 				.run((context) -> assertThat(
@@ -105,7 +106,7 @@ class JpaRepositoriesAutoConfigurationTests {
 	}
 
 	@Test
-	void whenBootstrappingModeIsDeferredBootstrapExecutorIsConfigured() {
+	void whenBootstrapModeIsDeferredBootstrapExecutorIsConfigured() {
 		this.contextRunner.withUserConfiguration(MultipleAsyncTaskExecutorConfiguration.class)
 				.withConfiguration(AutoConfigurations.of(TaskExecutionAutoConfiguration.class,
 						TaskSchedulingAutoConfiguration.class))
@@ -116,7 +117,7 @@ class JpaRepositoriesAutoConfigurationTests {
 	}
 
 	@Test
-	void whenBootstrappingModeIsDefaultBootstrapExecutorIsNotConfigured() {
+	void whenBootstrapModeIsDefaultBootstrapExecutorIsNotConfigured() {
 		this.contextRunner.withUserConfiguration(MultipleAsyncTaskExecutorConfiguration.class)
 				.withConfiguration(AutoConfigurations.of(TaskExecutionAutoConfiguration.class,
 						TaskSchedulingAutoConfiguration.class))
@@ -124,6 +125,16 @@ class JpaRepositoriesAutoConfigurationTests {
 						context.getBean(LocalContainerEntityManagerFactoryBean.class).getBootstrapExecutor()).isNull());
 	}
 
+	@Test
+	void bootstrapModeIsDeferredByDefault() {
+		this.contextRunner.withUserConfiguration(MultipleAsyncTaskExecutorConfiguration.class)
+				.withConfiguration(AutoConfigurations.of(TaskExecutionAutoConfiguration.class,
+						TaskSchedulingAutoConfiguration.class))
+				.run((context) -> assertThat(
+						context.getBean(LocalContainerEntityManagerFactoryBean.class).getBootstrapExecutor())
+								.isEqualTo(context.getBean("applicationTaskExecutor")));
+	}
+
 	@Configuration(proxyBeanMethods = false)
 	@EnableScheduling
 	@Import(TestConfiguration.class)