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

 /*
- * 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

 /*
- * 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

 /*
- * 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)

spring-boot-project/spring-boot-test-autoconfigure/src/main/java/org/springframework/boot/test/autoconfigure/orm/jpa/DataJpaTest.java

 /*
- * 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.
@@ -36,6 +36,7 @@ import org.springframework.boot.test.context.SpringBootTest;
 import org.springframework.context.annotation.ComponentScan.Filter;
 import org.springframework.core.annotation.AliasFor;
 import org.springframework.core.env.Environment;
+import org.springframework.data.repository.config.BootstrapMode;
 import org.springframework.test.context.BootstrapWith;
 import org.springframework.test.context.junit.jupiter.SpringExtension;
 import org.springframework.transaction.annotation.Transactional;
@@ -62,6 +63,7 @@ import org.springframework.transaction.annotation.Transactional;
  *
  * @author Phillip Webb
  * @author Artsiom Yudovin
+ * @author Scott Frederick
  * @since 1.4.0
  * @see AutoConfigureDataJpa
  * @see AutoConfigureTestDatabase
@@ -99,6 +101,14 @@ public @interface DataJpaTest {
 	@PropertyMapping("spring.jpa.show-sql")
 	boolean showSql() default true;
 
+	/**
+	 * The {@link BootstrapMode} for the test repository support. Defaults to
+	 * {@link BootstrapMode#LAZY}.
+	 * @return the {@link BootstrapMode} to use for test the repository
+	 */
+	@PropertyMapping("spring.data.jpa.repositories.bootstrap-mode")
+	BootstrapMode bootstrapMode() default BootstrapMode.LAZY;
+
 	/**
 	 * Determines if default filtering should be used with
 	 * {@link SpringBootApplication @SpringBootApplication}. By default no beans are

spring-boot-project/spring-boot-test-autoconfigure/src/test/java/org/springframework/boot/test/autoconfigure/orm/jpa/DataJpaTestPropertiesIntegrationTests.java → spring-boot-project/spring-boot-test-autoconfigure/src/test/java/org/springframework/boot/test/autoconfigure/orm/jpa/DataJpaTestAttributesIntegrationTests.java

 /*
- * 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.
@@ -20,17 +20,18 @@ import org.junit.jupiter.api.Test;
 
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.core.env.Environment;
+import org.springframework.data.repository.config.BootstrapMode;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
 /**
- * Tests for the {@link DataJpaTest#properties properties} attribute of
- * {@link DataJpaTest @DataJpaTest}.
+ * Tests for non-default attributes of {@link DataJpaTest @DataJpaTest}.
  *
  * @author Artsiom Yudovin
+ * @author Scott Frederick
  */
-@DataJpaTest(properties = "spring.profiles.active=test")
-class DataJpaTestPropertiesIntegrationTests {
+@DataJpaTest(properties = "spring.profiles.active=test", bootstrapMode = BootstrapMode.DEFERRED)
+class DataJpaTestAttributesIntegrationTests {
 
 	@Autowired
 	private Environment environment;
@@ -40,4 +41,10 @@ class DataJpaTestPropertiesIntegrationTests {
 		assertThat(this.environment.getActiveProfiles()).containsExactly("test");
 	}
 
+	@Test
+	void bootstrapModeIsSet() {
+		assertThat(this.environment.getProperty("spring.data.jpa.repositories.bootstrap-mode"))
+				.isEqualTo(BootstrapMode.DEFERRED.name());
+	}
+
 }

spring-boot-project/spring-boot-test-autoconfigure/src/test/java/org/springframework/boot/test/autoconfigure/orm/jpa/DataJpaTestIntegrationTests.java

 /*
- * 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.
@@ -25,6 +25,7 @@ import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.autoconfigure.flyway.FlywayAutoConfiguration;
 import org.springframework.boot.autoconfigure.liquibase.LiquibaseAutoConfiguration;
 import org.springframework.context.ApplicationContext;
+import org.springframework.data.repository.config.BootstrapMode;
 import org.springframework.jdbc.core.JdbcTemplate;
 import org.springframework.test.context.TestPropertySource;
 
@@ -37,6 +38,7 @@ import static org.springframework.boot.test.autoconfigure.AutoConfigurationImpor
  *
  * @author Phillip Webb
  * @author Andy Wilkinson
+ * @author Scott Frederick
  */
 @DataJpaTest
 @TestPropertySource(properties = "spring.jpa.hibernate.use-new-id-generator-mappings=false")
@@ -106,4 +108,10 @@ class DataJpaTestIntegrationTests {
 		assertThat(this.applicationContext).has(importedAutoConfiguration(LiquibaseAutoConfiguration.class));
 	}
 
+	@Test
+	void bootstrapModeIsLazyByDefault() {
+		assertThat(this.applicationContext.getEnvironment().getProperty("spring.data.jpa.repositories.bootstrap-mode"))
+				.isEqualTo(BootstrapMode.LAZY.name());
+	}
+
 }