Restructure bootstrap classes to a foundational layer

Move bootstrap code from `org.springframework.boot` to
`org.springframework.boot.bootstrap` and make them a foundational
layer.

This move helps reduce `org.springframework.boot.context.config`
dependencies to `org.springframework.boot`.

See gh-47232

config/checkstyle/import-control.xml

@@ -13,7 +13,10 @@
 	<!-- Allow other imports -->
 	<allow pkg=".*" regex="true" />
 
-	<!-- Keep foundation packages away from SpringApplication package -->
+	<!-- Keep foundation packages away from 'org.springframework.boot' package -->
+	<subpackage name="bootstrap">
+		<disallow pkg="org.springframework.boot" exact-match="true"/>
+	</subpackage>
 	<subpackage name="ssl">
 		<disallow pkg="org.springframework.boot" exact-match="true"/>
 	</subpackage>

core/spring-boot-test/src/main/java/org/springframework/boot/test/context/ConfigDataApplicationContextInitializer.java

@@ -16,8 +16,8 @@
 
 package org.springframework.boot.test.context;
 
-import org.springframework.boot.DefaultBootstrapContext;
 import org.springframework.boot.DefaultPropertiesPropertySource;
+import org.springframework.boot.bootstrap.DefaultBootstrapContext;
 import org.springframework.boot.context.config.ConfigData;
 import org.springframework.boot.context.config.ConfigDataEnvironmentPostProcessor;
 import org.springframework.boot.env.RandomValuePropertySource;

core/spring-boot-test/src/main/java/org/springframework/boot/test/context/SpringBootContextLoader.java

@@ -30,13 +30,13 @@ import org.springframework.aot.hint.RuntimeHints;
 import org.springframework.beans.BeanUtils;
 import org.springframework.boot.ApplicationContextFactory;
 import org.springframework.boot.Banner;
-import org.springframework.boot.ConfigurableBootstrapContext;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.SpringApplication.AbandonedRunException;
 import org.springframework.boot.SpringApplicationHook;
 import org.springframework.boot.SpringApplicationRunListener;
 import org.springframework.boot.SpringBootConfiguration;
 import org.springframework.boot.WebApplicationType;
+import org.springframework.boot.bootstrap.ConfigurableBootstrapContext;
 import org.springframework.boot.context.event.ApplicationEnvironmentPreparedEvent;
 import org.springframework.boot.test.context.SpringBootTest.UseMainMethod;
 import org.springframework.boot.test.mock.web.SpringBootMockServletContext;

core/spring-boot/src/main/java/org/springframework/boot/SpringApplication.java

@@ -58,6 +58,9 @@ import org.springframework.beans.factory.support.DefaultListableBeanFactory;
 import org.springframework.beans.factory.support.RootBeanDefinition;
 import org.springframework.beans.factory.xml.XmlBeanDefinitionReader;
 import org.springframework.boot.Banner.Mode;
+import org.springframework.boot.bootstrap.BootstrapRegistry;
+import org.springframework.boot.bootstrap.BootstrapRegistryInitializer;
+import org.springframework.boot.bootstrap.DefaultBootstrapContext;
 import org.springframework.boot.context.properties.bind.Bindable;
 import org.springframework.boot.context.properties.bind.Binder;
 import org.springframework.boot.context.properties.source.ConfigurationPropertySources;

core/spring-boot/src/main/java/org/springframework/boot/SpringApplicationRunListener.java

@@ -20,6 +20,7 @@ import java.time.Duration;
 
 import org.jspecify.annotations.Nullable;
 
+import org.springframework.boot.bootstrap.ConfigurableBootstrapContext;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.ConfigurableApplicationContext;
 import org.springframework.core.env.ConfigurableEnvironment;

core/spring-boot/src/main/java/org/springframework/boot/SpringApplicationRunListeners.java

@@ -23,6 +23,7 @@ import java.util.function.Consumer;
 import org.apache.commons.logging.Log;
 import org.jspecify.annotations.Nullable;
 
+import org.springframework.boot.bootstrap.ConfigurableBootstrapContext;
 import org.springframework.context.ConfigurableApplicationContext;
 import org.springframework.core.env.ConfigurableEnvironment;
 import org.springframework.core.metrics.ApplicationStartup;

core/spring-boot/src/main/java/org/springframework/boot/bootstrap/BootstrapContext.java

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.springframework.boot;
+package org.springframework.boot.bootstrap;
 
 import java.util.function.Supplier;
 
@@ -31,7 +31,7 @@ import org.springframework.core.env.Environment;
  * shared before the {@link ApplicationContext} is available.
  *
  * @author Phillip Webb
- * @since 2.4.0
+ * @since 4.0.0
  */
 public interface BootstrapContext {
 

core/spring-boot/src/main/java/org/springframework/boot/bootstrap/BootstrapContextClosedEvent.java

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.springframework.boot;
+package org.springframework.boot.bootstrap;
 
 import org.springframework.context.ApplicationEvent;
 import org.springframework.context.ConfigurableApplicationContext;
@@ -23,7 +23,7 @@ import org.springframework.context.ConfigurableApplicationContext;
  * {@link ApplicationEvent} published by a {@link BootstrapContext} when it's closed.
  *
  * @author Phillip Webb
- * @since 2.4.0
+ * @since 4.0.0
  * @see BootstrapRegistry#addCloseListener(org.springframework.context.ApplicationListener)
  */
 public class BootstrapContextClosedEvent extends ApplicationEvent {

core/spring-boot/src/main/java/org/springframework/boot/bootstrap/BootstrapRegistry.java

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.springframework.boot;
+package org.springframework.boot.bootstrap;
 
 import java.util.function.Supplier;
 
@@ -42,7 +42,7 @@ import org.springframework.util.Assert;
  * use.
  *
  * @author Phillip Webb
- * @since 2.4.0
+ * @since 4.0.0
  * @see BootstrapContext
  * @see ConfigurableBootstrapContext
  */

core/spring-boot/src/main/java/org/springframework/boot/bootstrap/BootstrapRegistryInitializer.java

@@ -14,15 +14,14 @@
  * limitations under the License.
  */
 
-package org.springframework.boot;
+package org.springframework.boot.bootstrap;
 
 /**
  * Callback interface that can be used to initialize a {@link BootstrapRegistry} before it
  * is used.
  *
  * @author Phillip Webb
- * @since 2.4.5
- * @see SpringApplication#addBootstrapRegistryInitializer(BootstrapRegistryInitializer)
+ * @since 4.0.0
  * @see BootstrapRegistry
  */
 @FunctionalInterface

core/spring-boot/src/main/java/org/springframework/boot/bootstrap/ConfigurableBootstrapContext.java

@@ -14,14 +14,14 @@
  * limitations under the License.
  */
 
-package org.springframework.boot;
+package org.springframework.boot.bootstrap;
 
 /**
  * A {@link BootstrapContext} that also provides configuration methods through the
  * {@link BootstrapRegistry} interface.
  *
  * @author Phillip Webb
- * @since 2.4.0
+ * @since 4.0.0
  * @see BootstrapRegistry
  * @see BootstrapContext
  * @see DefaultBootstrapContext

core/spring-boot/src/main/java/org/springframework/boot/bootstrap/DefaultBootstrapContext.java

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.springframework.boot;
+package org.springframework.boot.bootstrap;
 
 import java.util.HashMap;
 import java.util.Map;
@@ -33,7 +33,7 @@ import org.springframework.util.Assert;
  * Default {@link ConfigurableBootstrapContext} implementation.
  *
  * @author Phillip Webb
- * @since 2.4.0
+ * @since 4.0.0
  */
 public class DefaultBootstrapContext implements ConfigurableBootstrapContext {
 

core/spring-boot/src/main/java/org/springframework/boot/bootstrap/package-info.java

@@ -0,0 +1,24 @@
+/*
+ * Copyright 2012-present 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * Bootstrap concerns to support the creation of potentially expensive singletons while
+ * the application starts.
+ */
+@NullMarked
+package org.springframework.boot.bootstrap;
+
+import org.jspecify.annotations.NullMarked;

core/spring-boot/src/main/java/org/springframework/boot/builder/SpringApplicationBuilder.java

@@ -33,10 +33,10 @@ import org.springframework.beans.factory.support.AbstractAutowireCapableBeanFact
 import org.springframework.beans.factory.support.BeanNameGenerator;
 import org.springframework.boot.ApplicationContextFactory;
 import org.springframework.boot.Banner;
-import org.springframework.boot.BootstrapRegistry;
-import org.springframework.boot.BootstrapRegistryInitializer;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.WebApplicationType;
+import org.springframework.boot.bootstrap.BootstrapRegistry;
+import org.springframework.boot.bootstrap.BootstrapRegistryInitializer;
 import org.springframework.boot.convert.ApplicationConversionService;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.ApplicationContextInitializer;

core/spring-boot/src/main/java/org/springframework/boot/context/config/ConfigDataEnvironment.java

@@ -26,10 +26,10 @@ import java.util.Set;
 import org.apache.commons.logging.Log;
 import org.jspecify.annotations.Nullable;
 
-import org.springframework.boot.BootstrapRegistry.InstanceSupplier;
-import org.springframework.boot.BootstrapRegistry.Scope;
-import org.springframework.boot.ConfigurableBootstrapContext;
 import org.springframework.boot.DefaultPropertiesPropertySource;
+import org.springframework.boot.bootstrap.BootstrapRegistry.InstanceSupplier;
+import org.springframework.boot.bootstrap.BootstrapRegistry.Scope;
+import org.springframework.boot.bootstrap.ConfigurableBootstrapContext;
 import org.springframework.boot.context.config.ConfigDataEnvironmentContributors.BinderOption;
 import org.springframework.boot.context.properties.bind.BindException;
 import org.springframework.boot.context.properties.bind.Bindable;

core/spring-boot/src/main/java/org/springframework/boot/context/config/ConfigDataEnvironmentContributors.java

@@ -29,7 +29,7 @@ import java.util.function.Predicate;
 import org.apache.commons.logging.Log;
 import org.jspecify.annotations.Nullable;
 
-import org.springframework.boot.ConfigurableBootstrapContext;
+import org.springframework.boot.bootstrap.ConfigurableBootstrapContext;
 import org.springframework.boot.context.config.ConfigDataEnvironmentContributor.ImportPhase;
 import org.springframework.boot.context.config.ConfigDataEnvironmentContributor.Kind;
 import org.springframework.boot.context.properties.bind.BindContext;

core/spring-boot/src/main/java/org/springframework/boot/context/config/ConfigDataEnvironmentPostProcessor.java

@@ -24,9 +24,9 @@ import java.util.function.Supplier;
 import org.apache.commons.logging.Log;
 import org.jspecify.annotations.Nullable;
 
-import org.springframework.boot.ConfigurableBootstrapContext;
-import org.springframework.boot.DefaultBootstrapContext;
 import org.springframework.boot.SpringApplication;
+import org.springframework.boot.bootstrap.ConfigurableBootstrapContext;
+import org.springframework.boot.bootstrap.DefaultBootstrapContext;
 import org.springframework.boot.env.EnvironmentPostProcessor;
 import org.springframework.boot.logging.DeferredLogFactory;
 import org.springframework.core.Ordered;

core/spring-boot/src/main/java/org/springframework/boot/context/config/ConfigDataLoader.java

@@ -20,9 +20,9 @@ import java.io.IOException;
 
 import org.jspecify.annotations.Nullable;
 
-import org.springframework.boot.BootstrapContext;
-import org.springframework.boot.BootstrapRegistry;
-import org.springframework.boot.ConfigurableBootstrapContext;
+import org.springframework.boot.bootstrap.BootstrapContext;
+import org.springframework.boot.bootstrap.BootstrapRegistry;
+import org.springframework.boot.bootstrap.ConfigurableBootstrapContext;
 import org.springframework.boot.logging.DeferredLogFactory;
 
 /**

core/spring-boot/src/main/java/org/springframework/boot/context/config/ConfigDataLoaderContext.java

@@ -16,7 +16,7 @@
 
 package org.springframework.boot.context.config;
 
-import org.springframework.boot.ConfigurableBootstrapContext;
+import org.springframework.boot.bootstrap.ConfigurableBootstrapContext;
 import org.springframework.boot.env.EnvironmentPostProcessor;
 
 /**

core/spring-boot/src/main/java/org/springframework/boot/context/config/ConfigDataLoaders.java

@@ -24,9 +24,9 @@ import java.util.List;
 import org.apache.commons.logging.Log;
 import org.jspecify.annotations.Nullable;
 
-import org.springframework.boot.BootstrapContext;
-import org.springframework.boot.BootstrapRegistry;
-import org.springframework.boot.ConfigurableBootstrapContext;
+import org.springframework.boot.bootstrap.BootstrapContext;
+import org.springframework.boot.bootstrap.BootstrapRegistry;
+import org.springframework.boot.bootstrap.ConfigurableBootstrapContext;
 import org.springframework.boot.logging.DeferredLogFactory;
 import org.springframework.core.ResolvableType;
 import org.springframework.core.io.support.SpringFactoriesLoader;

core/spring-boot/src/main/java/org/springframework/boot/context/config/ConfigDataLocationResolver.java

@@ -19,9 +19,9 @@ package org.springframework.boot.context.config;
 import java.util.Collections;
 import java.util.List;
 
-import org.springframework.boot.BootstrapContext;
-import org.springframework.boot.BootstrapRegistry;
-import org.springframework.boot.ConfigurableBootstrapContext;
+import org.springframework.boot.bootstrap.BootstrapContext;
+import org.springframework.boot.bootstrap.BootstrapRegistry;
+import org.springframework.boot.bootstrap.ConfigurableBootstrapContext;
 import org.springframework.boot.context.properties.bind.Binder;
 import org.springframework.boot.logging.DeferredLogFactory;
 import org.springframework.core.Ordered;

core/spring-boot/src/main/java/org/springframework/boot/context/config/ConfigDataLocationResolverContext.java

@@ -18,7 +18,7 @@ package org.springframework.boot.context.config;
 
 import org.jspecify.annotations.Nullable;
 
-import org.springframework.boot.ConfigurableBootstrapContext;
+import org.springframework.boot.bootstrap.ConfigurableBootstrapContext;
 import org.springframework.boot.context.properties.bind.Binder;
 import org.springframework.boot.env.EnvironmentPostProcessor;
 

core/spring-boot/src/main/java/org/springframework/boot/context/config/ConfigDataLocationResolvers.java

@@ -24,9 +24,9 @@ import java.util.function.Supplier;
 import org.apache.commons.logging.Log;
 import org.jspecify.annotations.Nullable;
 
-import org.springframework.boot.BootstrapContext;
-import org.springframework.boot.BootstrapRegistry;
-import org.springframework.boot.ConfigurableBootstrapContext;
+import org.springframework.boot.bootstrap.BootstrapContext;
+import org.springframework.boot.bootstrap.BootstrapRegistry;
+import org.springframework.boot.bootstrap.ConfigurableBootstrapContext;
 import org.springframework.boot.context.properties.bind.Binder;
 import org.springframework.boot.logging.DeferredLogFactory;
 import org.springframework.core.env.Environment;

core/spring-boot/src/main/java/org/springframework/boot/context/event/ApplicationEnvironmentPreparedEvent.java

@@ -16,8 +16,8 @@
 
 package org.springframework.boot.context.event;
 
-import org.springframework.boot.ConfigurableBootstrapContext;
 import org.springframework.boot.SpringApplication;
+import org.springframework.boot.bootstrap.ConfigurableBootstrapContext;
 import org.springframework.core.env.ConfigurableEnvironment;
 import org.springframework.core.env.Environment;
 

core/spring-boot/src/main/java/org/springframework/boot/context/event/ApplicationStartingEvent.java

@@ -16,8 +16,8 @@
 
 package org.springframework.boot.context.event;
 
-import org.springframework.boot.ConfigurableBootstrapContext;
 import org.springframework.boot.SpringApplication;
+import org.springframework.boot.bootstrap.ConfigurableBootstrapContext;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.ApplicationListener;
 import org.springframework.core.env.Environment;

core/spring-boot/src/main/java/org/springframework/boot/context/event/EventPublishingRunListener.java

@@ -22,12 +22,12 @@ import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.jspecify.annotations.Nullable;
 
-import org.springframework.boot.ConfigurableBootstrapContext;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.SpringApplicationRunListener;
 import org.springframework.boot.availability.AvailabilityChangeEvent;
 import org.springframework.boot.availability.LivenessState;
 import org.springframework.boot.availability.ReadinessState;
+import org.springframework.boot.bootstrap.ConfigurableBootstrapContext;
 import org.springframework.context.ApplicationContextAware;
 import org.springframework.context.ApplicationEvent;
 import org.springframework.context.ApplicationListener;

core/spring-boot/src/main/java/org/springframework/boot/env/EnvironmentPostProcessor.java

@@ -16,10 +16,10 @@
 
 package org.springframework.boot.env;
 
-import org.springframework.boot.BootstrapContext;
-import org.springframework.boot.BootstrapRegistry;
-import org.springframework.boot.ConfigurableBootstrapContext;
 import org.springframework.boot.SpringApplication;
+import org.springframework.boot.bootstrap.BootstrapContext;
+import org.springframework.boot.bootstrap.BootstrapRegistry;
+import org.springframework.boot.bootstrap.ConfigurableBootstrapContext;
 import org.springframework.boot.logging.DeferredLogFactory;
 import org.springframework.core.env.ConfigurableEnvironment;
 import org.springframework.core.env.Environment;

core/spring-boot/src/main/java/org/springframework/boot/env/EnvironmentPostProcessorApplicationListener.java

@@ -33,8 +33,8 @@ import org.springframework.beans.factory.aot.BeanFactoryInitializationAotContrib
 import org.springframework.beans.factory.aot.BeanFactoryInitializationAotProcessor;
 import org.springframework.beans.factory.aot.BeanFactoryInitializationCode;
 import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
-import org.springframework.boot.ConfigurableBootstrapContext;
 import org.springframework.boot.SpringApplication;
+import org.springframework.boot.bootstrap.ConfigurableBootstrapContext;
 import org.springframework.boot.context.event.ApplicationEnvironmentPreparedEvent;
 import org.springframework.boot.context.event.ApplicationFailedEvent;
 import org.springframework.boot.context.event.ApplicationPreparedEvent;

core/spring-boot/src/main/java/org/springframework/boot/env/EnvironmentPostProcessorsFactory.java

@@ -20,7 +20,7 @@ import java.util.List;
 
 import org.jspecify.annotations.Nullable;
 
-import org.springframework.boot.ConfigurableBootstrapContext;
+import org.springframework.boot.bootstrap.ConfigurableBootstrapContext;
 import org.springframework.boot.logging.DeferredLogFactory;
 import org.springframework.core.io.support.SpringFactoriesLoader;
 

core/spring-boot/src/main/java/org/springframework/boot/env/ReflectionEnvironmentPostProcessorsFactory.java

@@ -23,9 +23,9 @@ import java.util.List;
 import org.apache.commons.logging.Log;
 import org.jspecify.annotations.Nullable;
 
-import org.springframework.boot.BootstrapContext;
-import org.springframework.boot.BootstrapRegistry;
-import org.springframework.boot.ConfigurableBootstrapContext;
+import org.springframework.boot.bootstrap.BootstrapContext;
+import org.springframework.boot.bootstrap.BootstrapRegistry;
+import org.springframework.boot.bootstrap.ConfigurableBootstrapContext;
 import org.springframework.boot.logging.DeferredLogFactory;
 import org.springframework.boot.util.Instantiator;
 import org.springframework.util.Assert;

core/spring-boot/src/main/java/org/springframework/boot/env/SpringFactoriesEnvironmentPostProcessorsFactory.java

@@ -18,9 +18,9 @@ package org.springframework.boot.env;
 
 import java.util.List;
 
-import org.springframework.boot.BootstrapContext;
-import org.springframework.boot.BootstrapRegistry;
-import org.springframework.boot.ConfigurableBootstrapContext;
+import org.springframework.boot.bootstrap.BootstrapContext;
+import org.springframework.boot.bootstrap.BootstrapRegistry;
+import org.springframework.boot.bootstrap.ConfigurableBootstrapContext;
 import org.springframework.boot.logging.DeferredLogFactory;
 import org.springframework.core.io.support.SpringFactoriesLoader;
 import org.springframework.core.io.support.SpringFactoriesLoader.ArgumentResolver;

core/spring-boot/src/test/java/org/springframework/boot/SpringApplicationTests.java

@@ -55,11 +55,11 @@ import org.springframework.beans.factory.support.BeanDefinitionRegistry;
 import org.springframework.beans.factory.support.BeanNameGenerator;
 import org.springframework.beans.factory.support.DefaultBeanNameGenerator;
 import org.springframework.boot.Banner.Mode;
-import org.springframework.boot.BootstrapRegistry.InstanceSupplier;
 import org.springframework.boot.availability.AvailabilityChangeEvent;
 import org.springframework.boot.availability.AvailabilityState;
 import org.springframework.boot.availability.LivenessState;
 import org.springframework.boot.availability.ReadinessState;
+import org.springframework.boot.bootstrap.BootstrapRegistry.InstanceSupplier;
 import org.springframework.boot.builder.ParentContextApplicationContextInitializer;
 import org.springframework.boot.builder.SpringApplicationBuilder;
 import org.springframework.boot.context.event.ApplicationContextInitializedEvent;

core/spring-boot/src/test/java/org/springframework/boot/bootstrap/DefaultBootstrapContextTests.java

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.springframework.boot;
+package org.springframework.boot.bootstrap;
 
 import java.io.IOException;
 import java.util.concurrent.atomic.AtomicInteger;
@@ -23,8 +23,8 @@ import org.assertj.core.api.AbstractAssert;
 import org.assertj.core.api.AssertProvider;
 import org.junit.jupiter.api.Test;
 
-import org.springframework.boot.BootstrapRegistry.InstanceSupplier;
-import org.springframework.boot.BootstrapRegistry.Scope;
+import org.springframework.boot.bootstrap.BootstrapRegistry.InstanceSupplier;
+import org.springframework.boot.bootstrap.BootstrapRegistry.Scope;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.ApplicationListener;
 import org.springframework.context.ConfigurableApplicationContext;

core/spring-boot/src/test/java/org/springframework/boot/context/ApplicationPidFileWriterTests.java

@@ -25,8 +25,8 @@ import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.io.TempDir;
 
-import org.springframework.boot.DefaultBootstrapContext;
 import org.springframework.boot.SpringApplication;
+import org.springframework.boot.bootstrap.DefaultBootstrapContext;
 import org.springframework.boot.context.event.ApplicationEnvironmentPreparedEvent;
 import org.springframework.boot.context.event.ApplicationPreparedEvent;
 import org.springframework.boot.context.event.ApplicationReadyEvent;

core/spring-boot/src/test/java/org/springframework/boot/context/FileEncodingApplicationListenerTests.java

@@ -18,8 +18,8 @@ package org.springframework.boot.context;
 
 import org.junit.jupiter.api.Test;
 
-import org.springframework.boot.DefaultBootstrapContext;
 import org.springframework.boot.SpringApplication;
+import org.springframework.boot.bootstrap.DefaultBootstrapContext;
 import org.springframework.boot.context.event.ApplicationEnvironmentPreparedEvent;
 import org.springframework.boot.context.properties.source.ConfigurationPropertySources;
 import org.springframework.core.env.ConfigurableEnvironment;

core/spring-boot/src/test/java/org/springframework/boot/context/config/ConfigDataEnvironmentContributorsTests.java

@@ -30,7 +30,7 @@ import org.junit.jupiter.api.extension.ExtendWith;
 import org.mockito.ArgumentCaptor;
 import org.mockito.junit.jupiter.MockitoExtension;
 
-import org.springframework.boot.DefaultBootstrapContext;
+import org.springframework.boot.bootstrap.DefaultBootstrapContext;
 import org.springframework.boot.cloud.CloudPlatform;
 import org.springframework.boot.context.config.ConfigDataEnvironmentContributor.Kind;
 import org.springframework.boot.context.config.ConfigDataEnvironmentContributors.BinderOption;

core/spring-boot/src/test/java/org/springframework/boot/context/config/ConfigDataEnvironmentPostProcessorBootstrapContextIntegrationTests.java

@@ -19,9 +19,9 @@ package org.springframework.boot.context.config;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
-import org.springframework.boot.BootstrapRegistry;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.WebApplicationType;
+import org.springframework.boot.bootstrap.BootstrapRegistry;
 import org.springframework.boot.context.config.TestConfigDataBootstrap.LoaderHelper;
 import org.springframework.boot.testsupport.classpath.resources.WithResource;
 import org.springframework.context.ConfigurableApplicationContext;

core/spring-boot/src/test/java/org/springframework/boot/context/config/ConfigDataEnvironmentPostProcessorTests.java

@@ -21,9 +21,9 @@ import java.util.function.Supplier;
 
 import org.junit.jupiter.api.Test;
 
-import org.springframework.boot.DefaultBootstrapContext;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.TestApplicationEnvironment;
+import org.springframework.boot.bootstrap.DefaultBootstrapContext;
 import org.springframework.boot.context.config.ConfigData.Options;
 import org.springframework.boot.testsupport.classpath.resources.WithResource;
 import org.springframework.core.env.PropertySource;

core/spring-boot/src/test/java/org/springframework/boot/context/config/ConfigDataEnvironmentTests.java

@@ -32,9 +32,9 @@ import org.junit.jupiter.api.TestInfo;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.ValueSource;
 
-import org.springframework.boot.ConfigurableBootstrapContext;
-import org.springframework.boot.DefaultBootstrapContext;
 import org.springframework.boot.MockApplicationEnvironment;
+import org.springframework.boot.bootstrap.ConfigurableBootstrapContext;
+import org.springframework.boot.bootstrap.DefaultBootstrapContext;
 import org.springframework.boot.context.config.ConfigDataEnvironmentContributor.ImportPhase;
 import org.springframework.boot.context.config.ConfigDataEnvironmentContributor.Kind;
 import org.springframework.boot.context.config.TestConfigDataEnvironmentUpdateListener.AddedPropertySource;

core/spring-boot/src/test/java/org/springframework/boot/context/config/ConfigDataLoadersTests.java

@@ -27,11 +27,11 @@ import org.assertj.core.api.InstanceOfAssertFactories;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.io.TempDir;
 
-import org.springframework.boot.BootstrapContext;
-import org.springframework.boot.BootstrapRegistry;
-import org.springframework.boot.BootstrapRegistry.InstanceSupplier;
-import org.springframework.boot.ConfigurableBootstrapContext;
-import org.springframework.boot.DefaultBootstrapContext;
+import org.springframework.boot.bootstrap.BootstrapContext;
+import org.springframework.boot.bootstrap.BootstrapRegistry;
+import org.springframework.boot.bootstrap.BootstrapRegistry.InstanceSupplier;
+import org.springframework.boot.bootstrap.ConfigurableBootstrapContext;
+import org.springframework.boot.bootstrap.DefaultBootstrapContext;
 import org.springframework.boot.logging.DeferredLogFactory;
 import org.springframework.core.env.PropertySource;
 import org.springframework.core.test.io.support.MockSpringFactoriesLoader;

core/spring-boot/src/test/java/org/springframework/boot/context/config/ConfigDataLocationResolversTests.java

@@ -27,11 +27,11 @@ import org.junit.jupiter.api.io.TempDir;
 import org.mockito.Mock;
 import org.mockito.junit.jupiter.MockitoExtension;
 
-import org.springframework.boot.BootstrapContext;
-import org.springframework.boot.BootstrapRegistry;
-import org.springframework.boot.BootstrapRegistry.InstanceSupplier;
-import org.springframework.boot.ConfigurableBootstrapContext;
-import org.springframework.boot.DefaultBootstrapContext;
+import org.springframework.boot.bootstrap.BootstrapContext;
+import org.springframework.boot.bootstrap.BootstrapRegistry;
+import org.springframework.boot.bootstrap.BootstrapRegistry.InstanceSupplier;
+import org.springframework.boot.bootstrap.ConfigurableBootstrapContext;
+import org.springframework.boot.bootstrap.DefaultBootstrapContext;
 import org.springframework.boot.context.properties.bind.Binder;
 import org.springframework.boot.logging.DeferredLogFactory;
 import org.springframework.core.Ordered;

core/spring-boot/src/test/java/org/springframework/boot/context/config/TestConfigDataBootstrap.java

@@ -21,8 +21,8 @@ import java.util.Collections;
 import java.util.List;
 import java.util.function.Supplier;
 
-import org.springframework.boot.BootstrapContextClosedEvent;
-import org.springframework.boot.BootstrapRegistry.InstanceSupplier;
+import org.springframework.boot.bootstrap.BootstrapContextClosedEvent;
+import org.springframework.boot.bootstrap.BootstrapRegistry.InstanceSupplier;
 import org.springframework.boot.context.properties.bind.Binder;
 import org.springframework.context.ApplicationListener;
 import org.springframework.core.env.MapPropertySource;

core/spring-boot/src/test/java/org/springframework/boot/context/event/EventPublishingRunListenerTests.java

@@ -24,9 +24,9 @@ import java.util.List;
 
 import org.junit.jupiter.api.Test;
 
-import org.springframework.boot.DefaultBootstrapContext;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.availability.AvailabilityChangeEvent;
+import org.springframework.boot.bootstrap.DefaultBootstrapContext;
 import org.springframework.context.ApplicationEvent;
 import org.springframework.context.ApplicationListener;
 import org.springframework.context.support.StaticApplicationContext;

core/spring-boot/src/test/java/org/springframework/boot/context/logging/LoggingApplicationListenerTests.java

@@ -48,9 +48,9 @@ import org.junit.jupiter.api.io.TempDir;
 import org.slf4j.LoggerFactory;
 import org.slf4j.bridge.SLF4JBridgeHandler;
 
-import org.springframework.boot.DefaultBootstrapContext;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.WebApplicationType;
+import org.springframework.boot.bootstrap.DefaultBootstrapContext;
 import org.springframework.boot.context.event.ApplicationFailedEvent;
 import org.springframework.boot.context.event.ApplicationStartingEvent;
 import org.springframework.boot.context.properties.bind.BindException;

core/spring-boot/src/test/java/org/springframework/boot/env/EnvironmentPostProcessorApplicationListenerTests.java

@@ -38,10 +38,10 @@ import org.springframework.aot.AotDetector;
 import org.springframework.aot.test.generate.TestGenerationContext;
 import org.springframework.beans.factory.aot.BeanFactoryInitializationAotContribution;
 import org.springframework.beans.factory.support.DefaultListableBeanFactory;
-import org.springframework.boot.BootstrapRegistry;
-import org.springframework.boot.DefaultBootstrapContext;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.WebApplicationType;
+import org.springframework.boot.bootstrap.BootstrapRegistry;
+import org.springframework.boot.bootstrap.DefaultBootstrapContext;
 import org.springframework.boot.context.event.ApplicationEnvironmentPreparedEvent;
 import org.springframework.boot.context.event.ApplicationFailedEvent;
 import org.springframework.boot.context.event.ApplicationPreparedEvent;

core/spring-boot/src/test/java/org/springframework/boot/env/EnvironmentPostProcessorsFactoryTests.java

@@ -21,8 +21,8 @@ import java.util.function.Supplier;
 
 import org.junit.jupiter.api.Test;
 
-import org.springframework.boot.DefaultBootstrapContext;
 import org.springframework.boot.SpringApplication;
+import org.springframework.boot.bootstrap.DefaultBootstrapContext;
 import org.springframework.boot.logging.DeferredLogFactory;
 import org.springframework.core.OverridingClassLoader;
 import org.springframework.core.env.ConfigurableEnvironment;

core/spring-boot/src/test/java/org/springframework/boot/env/ReflectionEnvironmentPostProcessorsFactoryTests.java

@@ -24,9 +24,9 @@ import java.util.function.Supplier;
 import org.apache.commons.logging.Log;
 import org.junit.jupiter.api.Test;
 
-import org.springframework.boot.BootstrapRegistry;
-import org.springframework.boot.DefaultBootstrapContext;
 import org.springframework.boot.SpringApplication;
+import org.springframework.boot.bootstrap.BootstrapRegistry;
+import org.springframework.boot.bootstrap.DefaultBootstrapContext;
 import org.springframework.boot.logging.DeferredLogFactory;
 import org.springframework.core.OverridingClassLoader;
 import org.springframework.core.env.ConfigurableEnvironment;

module/spring-boot-devtools/src/test/java/org/springframework/boot/devtools/restart/RestartApplicationListenerTests.java

@@ -23,8 +23,8 @@ import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
 
-import org.springframework.boot.DefaultBootstrapContext;
 import org.springframework.boot.SpringApplication;
+import org.springframework.boot.bootstrap.DefaultBootstrapContext;
 import org.springframework.boot.context.event.ApplicationFailedEvent;
 import org.springframework.boot.context.event.ApplicationPreparedEvent;
 import org.springframework.boot.context.event.ApplicationReadyEvent;

smoke-test/spring-boot-smoke-test-bootstrap-registry/src/main/java/smoketest/bootstrapregistry/external/svn/SubversionBootstrap.java

@@ -20,8 +20,8 @@ import java.util.function.Function;
 
 import org.jspecify.annotations.Nullable;
 
-import org.springframework.boot.BootstrapContext;
-import org.springframework.boot.BootstrapRegistryInitializer;
+import org.springframework.boot.bootstrap.BootstrapContext;
+import org.springframework.boot.bootstrap.BootstrapRegistryInitializer;
 
 /**
  * Allows the user to register a {@link BootstrapRegistryInitializer} with a custom

smoke-test/spring-boot-smoke-test-bootstrap-registry/src/main/java/smoketest/bootstrapregistry/external/svn/SubversionConfigDataLoader.java

@@ -19,10 +19,10 @@ package smoketest.bootstrapregistry.external.svn;
 import java.io.IOException;
 import java.util.Collections;
 
-import org.springframework.boot.BootstrapContext;
-import org.springframework.boot.BootstrapContextClosedEvent;
-import org.springframework.boot.BootstrapRegistry;
-import org.springframework.boot.BootstrapRegistry.InstanceSupplier;
+import org.springframework.boot.bootstrap.BootstrapContext;
+import org.springframework.boot.bootstrap.BootstrapContextClosedEvent;
+import org.springframework.boot.bootstrap.BootstrapRegistry;
+import org.springframework.boot.bootstrap.BootstrapRegistry.InstanceSupplier;
 import org.springframework.boot.context.config.ConfigData;
 import org.springframework.boot.context.config.ConfigDataLoader;
 import org.springframework.boot.context.config.ConfigDataLoaderContext;