Avoid defining nullability for non-relevant API

Defining nullability of some API like EnvironmentCapable
or ConditionContext causes issues in Spring Boot because
in the context where they are used, it is known for sure
they will return non-null values even if their API can in
other context return null values.

It is better in this case for both Java and Kotlin to
not define at all the nullabity of such API.

In practice, this is achieved by removing the package level
@NonNullApi annotation and adding it only on the
relevant classes.

Issue: SPR-15540

spring-context/src/main/java/org/springframework/context/annotation/AdviceModeImportSelector.java

@@ -21,6 +21,7 @@ import java.lang.annotation.Annotation;
 import org.springframework.core.GenericTypeResolver;
 import org.springframework.core.annotation.AnnotationAttributes;
 import org.springframework.core.type.AnnotationMetadata;
+import org.springframework.lang.NonNullApi;
 import org.springframework.lang.Nullable;
 
 /**
@@ -32,6 +33,7 @@ import org.springframework.lang.Nullable;
  * @since 3.1
  * @param <A> annotation containing {@linkplain #getAdviceModeAttributeName() AdviceMode attribute}
  */
+@NonNullApi
 public abstract class AdviceModeImportSelector<A extends Annotation> implements ImportSelector {
 
 	public static final String DEFAULT_ADVICE_MODE_ATTRIBUTE_NAME = "mode";

spring-context/src/main/java/org/springframework/context/annotation/AnnotatedBeanDefinitionReader.java

@@ -30,6 +30,7 @@ import org.springframework.beans.factory.support.BeanNameGenerator;
 import org.springframework.core.env.Environment;
 import org.springframework.core.env.EnvironmentCapable;
 import org.springframework.core.env.StandardEnvironment;
+import org.springframework.lang.NonNullApi;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 
@@ -45,6 +46,7 @@ import org.springframework.util.Assert;
  * @since 3.0
  * @see AnnotationConfigApplicationContext#register
  */
+@NonNullApi
 public class AnnotatedBeanDefinitionReader {
 
 	private final BeanDefinitionRegistry registry;

spring-context/src/main/java/org/springframework/context/annotation/AnnotationBeanNameGenerator.java

@@ -26,6 +26,7 @@ import org.springframework.beans.factory.support.BeanDefinitionRegistry;
 import org.springframework.beans.factory.support.BeanNameGenerator;
 import org.springframework.core.annotation.AnnotationAttributes;
 import org.springframework.core.type.AnnotationMetadata;
+import org.springframework.lang.NonNullApi;
 import org.springframework.lang.Nullable;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.StringUtils;
@@ -60,6 +61,7 @@ import org.springframework.util.StringUtils;
  * @see org.springframework.stereotype.Controller#value()
  * @see javax.inject.Named#value()
  */
+@NonNullApi
 public class AnnotationBeanNameGenerator implements BeanNameGenerator {
 
 	private static final String COMPONENT_ANNOTATION_CLASSNAME = "org.springframework.stereotype.Component";

spring-context/src/main/java/org/springframework/context/annotation/AnnotationConfigApplicationContext.java

@@ -23,6 +23,7 @@ import org.springframework.beans.factory.support.BeanNameGenerator;
 import org.springframework.beans.factory.support.DefaultListableBeanFactory;
 import org.springframework.context.support.GenericApplicationContext;
 import org.springframework.core.env.ConfigurableEnvironment;
+import org.springframework.lang.NonNullApi;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 
@@ -50,6 +51,7 @@ import org.springframework.util.Assert;
  * @see ClassPathBeanDefinitionScanner
  * @see org.springframework.context.support.GenericXmlApplicationContext
  */
+@NonNullApi
 public class AnnotationConfigApplicationContext extends GenericApplicationContext implements AnnotationConfigRegistry {
 
 	private final AnnotatedBeanDefinitionReader reader;

spring-context/src/main/java/org/springframework/context/annotation/AnnotationConfigBeanDefinitionParser.java

@@ -26,6 +26,7 @@ import org.springframework.beans.factory.parsing.BeanComponentDefinition;
 import org.springframework.beans.factory.parsing.CompositeComponentDefinition;
 import org.springframework.beans.factory.xml.BeanDefinitionParser;
 import org.springframework.beans.factory.xml.ParserContext;
+import org.springframework.lang.NonNullApi;
 
 /**
  * Parser for the <context:annotation-config/> element.
@@ -36,6 +37,7 @@ import org.springframework.beans.factory.xml.ParserContext;
  * @since 2.5
  * @see AnnotationConfigUtils
  */
+@NonNullApi
 public class AnnotationConfigBeanDefinitionParser implements BeanDefinitionParser {
 
 	@Override

spring-context/src/main/java/org/springframework/context/annotation/AnnotationConfigRegistry.java

@@ -16,6 +16,8 @@
 
 package org.springframework.context.annotation;
 
+import org.springframework.lang.NonNullApi;
+
 /**
  * Common interface for annotation config application contexts,
  * defining {@link #register} and {@link #scan} methods.
@@ -23,6 +25,7 @@ package org.springframework.context.annotation;
  * @author Juergen Hoeller
  * @since 4.1
  */
+@NonNullApi
 public interface AnnotationConfigRegistry {
 
 	/**

spring-context/src/main/java/org/springframework/context/annotation/AnnotationConfigUtils.java

@@ -37,6 +37,7 @@ import org.springframework.core.annotation.AnnotationAttributes;
 import org.springframework.core.annotation.AnnotationAwareOrderComparator;
 import org.springframework.core.type.AnnotatedTypeMetadata;
 import org.springframework.core.type.AnnotationMetadata;
+import org.springframework.lang.NonNullApi;
 import org.springframework.lang.Nullable;
 import org.springframework.util.ClassUtils;
 
@@ -60,6 +61,7 @@ import org.springframework.util.ClassUtils;
  * @see org.springframework.beans.factory.annotation.RequiredAnnotationBeanPostProcessor
  * @see org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor
  */
+@NonNullApi
 public class AnnotationConfigUtils {
 
 	/**

spring-context/src/main/java/org/springframework/context/annotation/AnnotationScopeMetadataResolver.java

@@ -21,6 +21,7 @@ import java.lang.annotation.Annotation;
 import org.springframework.beans.factory.annotation.AnnotatedBeanDefinition;
 import org.springframework.beans.factory.config.BeanDefinition;
 import org.springframework.core.annotation.AnnotationAttributes;
+import org.springframework.lang.NonNullApi;
 import org.springframework.util.Assert;
 
 /**
@@ -36,6 +37,7 @@ import org.springframework.util.Assert;
  * @since 2.5
  * @see org.springframework.context.annotation.Scope
  */
+@NonNullApi
 public class AnnotationScopeMetadataResolver implements ScopeMetadataResolver {
 
 	private final ScopedProxyMode defaultProxyMode;

spring-context/src/main/java/org/springframework/context/annotation/AspectJAutoProxyRegistrar.java

@@ -20,6 +20,7 @@ import org.springframework.aop.config.AopConfigUtils;
 import org.springframework.beans.factory.support.BeanDefinitionRegistry;
 import org.springframework.core.annotation.AnnotationAttributes;
 import org.springframework.core.type.AnnotationMetadata;
+import org.springframework.lang.NonNullApi;
 
 /**
  * Registers an {@link org.springframework.aop.aspectj.annotation.AnnotationAwareAspectJAutoProxyCreator
@@ -31,6 +32,7 @@ import org.springframework.core.type.AnnotationMetadata;
  * @since 3.1
  * @see EnableAspectJAutoProxy
  */
+@NonNullApi
 class AspectJAutoProxyRegistrar implements ImportBeanDefinitionRegistrar {
 
 	/**

spring-context/src/main/java/org/springframework/context/annotation/AutoProxyRegistrar.java

@@ -25,6 +25,7 @@ import org.springframework.aop.config.AopConfigUtils;
 import org.springframework.beans.factory.support.BeanDefinitionRegistry;
 import org.springframework.core.annotation.AnnotationAttributes;
 import org.springframework.core.type.AnnotationMetadata;
+import org.springframework.lang.NonNullApi;
 
 /**
  * Registers an auto proxy creator against the current {@link BeanDefinitionRegistry}
@@ -35,6 +36,7 @@ import org.springframework.core.type.AnnotationMetadata;
  * @since 3.1
  * @see EnableAspectJAutoProxy
  */
+@NonNullApi
 public class AutoProxyRegistrar implements ImportBeanDefinitionRegistrar {
 
 	private final Log logger = LogFactory.getLog(getClass());

spring-context/src/main/java/org/springframework/context/annotation/BeanAnnotationHelper.java

@@ -19,6 +19,7 @@ package org.springframework.context.annotation;
 import java.lang.reflect.Method;
 
 import org.springframework.core.annotation.AnnotatedElementUtils;
+import org.springframework.lang.NonNullApi;
 
 /**
  * Utilities for processing {@link Bean}-annotated methods.
@@ -27,6 +28,7 @@ import org.springframework.core.annotation.AnnotatedElementUtils;
  * @author Juergen Hoeller
  * @since 3.1
  */
+@NonNullApi
 class BeanAnnotationHelper {
 
 	public static boolean isBeanAnnotated(Method method) {

spring-context/src/main/java/org/springframework/context/annotation/BeanMethod.java

@@ -19,6 +19,7 @@ package org.springframework.context.annotation;
 import org.springframework.beans.factory.parsing.Problem;
 import org.springframework.beans.factory.parsing.ProblemReporter;
 import org.springframework.core.type.MethodMetadata;
+import org.springframework.lang.NonNullApi;
 
 /**
  * Represents a {@link Configuration} class method marked with the
@@ -31,6 +32,7 @@ import org.springframework.core.type.MethodMetadata;
  * @see ConfigurationClassParser
  * @see ConfigurationClassBeanDefinitionReader
  */
+@NonNullApi
 final class BeanMethod extends ConfigurationMethod {
 
 	public BeanMethod(MethodMetadata metadata, ConfigurationClass configurationClass) {

spring-context/src/main/java/org/springframework/context/annotation/ClassPathBeanDefinitionScanner.java

@@ -31,6 +31,7 @@ import org.springframework.core.env.Environment;
 import org.springframework.core.env.EnvironmentCapable;
 import org.springframework.core.env.StandardEnvironment;
 import org.springframework.core.io.ResourceLoader;
+import org.springframework.lang.NonNullApi;
 import org.springframework.util.Assert;
 import org.springframework.util.PatternMatchUtils;
 
@@ -59,6 +60,7 @@ import org.springframework.util.PatternMatchUtils;
  * @see org.springframework.stereotype.Service
  * @see org.springframework.stereotype.Controller
  */
+@NonNullApi
 public class ClassPathBeanDefinitionScanner extends ClassPathScanningCandidateComponentProvider {
 
 	private final BeanDefinitionRegistry registry;

spring-context/src/main/java/org/springframework/context/annotation/ClassPathScanningCandidateComponentProvider.java

@@ -51,6 +51,7 @@ import org.springframework.core.type.classreading.MetadataReaderFactory;
 import org.springframework.core.type.filter.AnnotationTypeFilter;
 import org.springframework.core.type.filter.AssignableTypeFilter;
 import org.springframework.core.type.filter.TypeFilter;
+import org.springframework.lang.NonNullApi;
 import org.springframework.lang.Nullable;
 import org.springframework.stereotype.Component;
 import org.springframework.stereotype.Controller;
@@ -84,6 +85,7 @@ import org.springframework.util.ClassUtils;
  * @see ScannedGenericBeanDefinition
  * @see CandidateComponentsIndex
  */
+@NonNullApi
 public class ClassPathScanningCandidateComponentProvider implements EnvironmentCapable, ResourceLoaderAware {
 
 	static final String DEFAULT_RESOURCE_PATTERN = "**/*.class";

spring-context/src/main/java/org/springframework/context/annotation/CommonAnnotationBeanPostProcessor.java

@@ -65,6 +65,7 @@ import org.springframework.core.BridgeMethodResolver;
 import org.springframework.core.MethodParameter;
 import org.springframework.core.Ordered;
 import org.springframework.jndi.support.SimpleJndiBeanFactory;
+import org.springframework.lang.NonNullApi;
 import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.ReflectionUtils;
@@ -139,6 +140,7 @@ import org.springframework.util.StringValueResolver;
  * @see org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor
  */
 @SuppressWarnings("serial")
+@NonNullApi
 public class CommonAnnotationBeanPostProcessor extends InitDestroyAnnotationBeanPostProcessor
 		implements InstantiationAwareBeanPostProcessor, BeanFactoryAware, Serializable {
 

spring-context/src/main/java/org/springframework/context/annotation/ComponentScanAnnotationParser.java

@@ -38,6 +38,7 @@ import org.springframework.core.type.filter.AspectJTypeFilter;
 import org.springframework.core.type.filter.AssignableTypeFilter;
 import org.springframework.core.type.filter.RegexPatternTypeFilter;
 import org.springframework.core.type.filter.TypeFilter;
+import org.springframework.lang.NonNullApi;
 import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.StringUtils;
@@ -52,6 +53,7 @@ import org.springframework.util.StringUtils;
  * @see ClassPathBeanDefinitionScanner#scan(String...)
  * @see ComponentScanBeanDefinitionParser
  */
+@NonNullApi
 class ComponentScanAnnotationParser {
 
 	private final Environment environment;

spring-context/src/main/java/org/springframework/context/annotation/ComponentScanBeanDefinitionParser.java

@@ -40,6 +40,7 @@ import org.springframework.core.type.filter.AspectJTypeFilter;
 import org.springframework.core.type.filter.AssignableTypeFilter;
 import org.springframework.core.type.filter.RegexPatternTypeFilter;
 import org.springframework.core.type.filter.TypeFilter;
+import org.springframework.lang.NonNullApi;
 import org.springframework.util.ReflectionUtils;
 import org.springframework.util.StringUtils;
 
@@ -51,6 +52,7 @@ import org.springframework.util.StringUtils;
  * @author Juergen Hoeller
  * @since 2.5
  */
+@NonNullApi
 public class ComponentScanBeanDefinitionParser implements BeanDefinitionParser {
 
 	private static final String BASE_PACKAGE_ATTRIBUTE = "base-package";

spring-context/src/main/java/org/springframework/context/annotation/Condition.java

@@ -18,6 +18,7 @@ package org.springframework.context.annotation;
 
 import org.springframework.beans.factory.config.BeanFactoryPostProcessor;
 import org.springframework.core.type.AnnotatedTypeMetadata;
+import org.springframework.lang.NonNullApi;
 
 /**
  * A single {@code condition} that must be {@linkplain #matches matched} in order
@@ -39,6 +40,7 @@ import org.springframework.core.type.AnnotatedTypeMetadata;
  * @see ConditionContext
  */
 @FunctionalInterface
+@NonNullApi
 public interface Condition {
 
 	/**

spring-context/src/main/java/org/springframework/context/annotation/ConditionContext.java

@@ -20,7 +20,6 @@ import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
 import org.springframework.beans.factory.support.BeanDefinitionRegistry;
 import org.springframework.core.env.Environment;
 import org.springframework.core.io.ResourceLoader;
-import org.springframework.lang.Nullable;
 
 /**
  * Context information for use by {@link Condition}s.
@@ -35,7 +34,6 @@ public interface ConditionContext {
 	 * should the condition match or {@code null} if the registry is not available.
 	 * @return the registry or {@code null}
 	 */
-	@Nullable
 	BeanDefinitionRegistry getRegistry();
 
 	/**
@@ -44,7 +42,6 @@ public interface ConditionContext {
 	 * is not available.
 	 * @return the bean factory or {@code null}
 	 */
-	@Nullable
 	ConfigurableListableBeanFactory getBeanFactory();
 
 	/**
@@ -52,7 +49,6 @@ public interface ConditionContext {
 	 * or {@code null} if no environment is available.
 	 * @return the environment or {@code null}
 	 */
-	@Nullable
 	Environment getEnvironment();
 
 	/**
@@ -60,7 +56,6 @@ public interface ConditionContext {
 	 * if the resource loader cannot be obtained.
 	 * @return a resource loader or {@code null}
 	 */
-	@Nullable
 	ResourceLoader getResourceLoader();
 
 	/**
@@ -68,7 +63,6 @@ public interface ConditionContext {
 	 * classes or {@code null} if the default classloader should be used.
 	 * @return the class loader or {@code null}
 	 */
-	@Nullable
 	ClassLoader getClassLoader();
 
 }

spring-context/src/main/java/org/springframework/context/annotation/ConditionEvaluator.java

@@ -31,6 +31,7 @@ import org.springframework.core.env.EnvironmentCapable;
 import org.springframework.core.io.ResourceLoader;
 import org.springframework.core.type.AnnotatedTypeMetadata;
 import org.springframework.core.type.AnnotationMetadata;
+import org.springframework.lang.NonNullApi;
 import org.springframework.lang.Nullable;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.MultiValueMap;
@@ -41,6 +42,7 @@ import org.springframework.util.MultiValueMap;
  * @author Phillip Webb
  * @since 4.0
  */
+@NonNullApi
 class ConditionEvaluator {
 
 	private final ConditionContextImpl context;

spring-context/src/main/java/org/springframework/context/annotation/ConfigurationClass.java

@@ -31,6 +31,7 @@ import org.springframework.core.io.Resource;
 import org.springframework.core.type.AnnotationMetadata;
 import org.springframework.core.type.StandardAnnotationMetadata;
 import org.springframework.core.type.classreading.MetadataReader;
+import org.springframework.lang.NonNullApi;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
@@ -47,6 +48,7 @@ import org.springframework.util.ClassUtils;
  * @see BeanMethod
  * @see ConfigurationClassParser
  */
+@NonNullApi
 final class ConfigurationClass {
 
 	private final AnnotationMetadata metadata;

spring-context/src/main/java/org/springframework/context/annotation/ConfigurationClassBeanDefinitionReader.java

@@ -50,6 +50,7 @@ import org.springframework.core.io.Resource;
 import org.springframework.core.io.ResourceLoader;
 import org.springframework.core.type.AnnotationMetadata;
 import org.springframework.core.type.MethodMetadata;
+import org.springframework.lang.NonNullApi;
 import org.springframework.util.StringUtils;
 
 /**
@@ -67,6 +68,7 @@ import org.springframework.util.StringUtils;
  * @since 3.0
  * @see ConfigurationClassParser
  */
+@NonNullApi
 class ConfigurationClassBeanDefinitionReader {
 
 	private static final Log logger = LogFactory.getLog(ConfigurationClassBeanDefinitionReader.class);

spring-context/src/main/java/org/springframework/context/annotation/ConfigurationClassEnhancer.java

@@ -49,6 +49,7 @@ import org.springframework.cglib.proxy.NoOp;
 import org.springframework.cglib.transform.ClassEmitterTransformer;
 import org.springframework.cglib.transform.TransformingClassGenerator;
 import org.springframework.core.annotation.AnnotatedElementUtils;
+import org.springframework.lang.NonNullApi;
 import org.springframework.lang.Nullable;
 import org.springframework.objenesis.ObjenesisException;
 import org.springframework.objenesis.SpringObjenesis;
@@ -72,6 +73,7 @@ import org.springframework.util.ReflectionUtils;
  * @see #enhance
  * @see ConfigurationClassPostProcessor
  */
+@NonNullApi
 class ConfigurationClassEnhancer {
 
 	// The callbacks to use. Note that these callbacks must be stateless.

spring-context/src/main/java/org/springframework/context/annotation/ConfigurationClassParser.java

@@ -72,6 +72,7 @@ import org.springframework.core.type.StandardAnnotationMetadata;
 import org.springframework.core.type.classreading.MetadataReader;
 import org.springframework.core.type.classreading.MetadataReaderFactory;
 import org.springframework.core.type.filter.AssignableTypeFilter;
+import org.springframework.lang.NonNullApi;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.CollectionUtils;
@@ -100,6 +101,7 @@ import org.springframework.util.StringUtils;
  * @since 3.0
  * @see ConfigurationClassBeanDefinitionReader
  */
+@NonNullApi
 class ConfigurationClassParser {
 
 	private static final PropertySourceFactory DEFAULT_PROPERTY_SOURCE_FACTORY = new DefaultPropertySourceFactory();

spring-context/src/main/java/org/springframework/context/annotation/ConfigurationClassPostProcessor.java

@@ -61,6 +61,7 @@ import org.springframework.core.io.ResourceLoader;
 import org.springframework.core.type.AnnotationMetadata;
 import org.springframework.core.type.classreading.CachingMetadataReaderFactory;
 import org.springframework.core.type.classreading.MetadataReaderFactory;
+import org.springframework.lang.NonNullApi;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
@@ -85,6 +86,7 @@ import static org.springframework.context.annotation.AnnotationConfigUtils.*;
  * @author Phillip Webb
  * @since 3.0
  */
+@NonNullApi
 public class ConfigurationClassPostProcessor implements BeanDefinitionRegistryPostProcessor,
 		PriorityOrdered, ResourceLoaderAware, BeanClassLoaderAware, EnvironmentAware {
 

spring-context/src/main/java/org/springframework/context/annotation/ConfigurationClassUtils.java

@@ -35,6 +35,7 @@ import org.springframework.core.type.AnnotationMetadata;
 import org.springframework.core.type.StandardAnnotationMetadata;
 import org.springframework.core.type.classreading.MetadataReader;
 import org.springframework.core.type.classreading.MetadataReaderFactory;
+import org.springframework.lang.NonNullApi;
 import org.springframework.stereotype.Component;
 
 /**
@@ -44,6 +45,7 @@ import org.springframework.stereotype.Component;
  * @author Juergen Hoeller
  * @since 3.1
  */
+@NonNullApi
 abstract class ConfigurationClassUtils {
 
 	private static final String CONFIGURATION_CLASS_FULL = "full";

spring-context/src/main/java/org/springframework/context/annotation/ConfigurationCondition.java

@@ -16,6 +16,8 @@
 
 package org.springframework.context.annotation;
 
+import org.springframework.lang.NonNullApi;
+
 /**
  * A {@link Condition} that offers more fine-grained control when used with
  * {@code @Configuration}. Allows certain {@link Condition}s to adapt when they match
@@ -27,6 +29,7 @@ package org.springframework.context.annotation;
  * @since 4.0
  * @see Configuration
  */
+@NonNullApi
 public interface ConfigurationCondition extends Condition {
 
 	/**

spring-context/src/main/java/org/springframework/context/annotation/ConfigurationMethod.java

@@ -19,11 +19,13 @@ package org.springframework.context.annotation;
 import org.springframework.beans.factory.parsing.Location;
 import org.springframework.beans.factory.parsing.ProblemReporter;
 import org.springframework.core.type.MethodMetadata;
+import org.springframework.lang.NonNullApi;
 
 /**
  * @author Chris Beams
  * @since 3.1
  */
+@NonNullApi
 abstract class ConfigurationMethod {
 
 	protected final MethodMetadata metadata;

spring-context/src/main/java/org/springframework/context/annotation/ConflictingBeanDefinitionException.java

@@ -16,6 +16,8 @@
 
 package org.springframework.context.annotation;
 
+import org.springframework.lang.NonNullApi;
+
 /**
  * Marker subclass of {@link IllegalStateException}, allowing for explicit
  * catch clauses in calling code.
@@ -24,6 +26,7 @@ package org.springframework.context.annotation;
  * @since 3.1
  */
 @SuppressWarnings("serial")
+@NonNullApi
 class ConflictingBeanDefinitionException extends IllegalStateException {
 
 	public ConflictingBeanDefinitionException(String message) {

spring-context/src/main/java/org/springframework/context/annotation/ContextAnnotationAutowireCandidateResolver.java

@@ -27,6 +27,7 @@ import org.springframework.beans.factory.config.DependencyDescriptor;
 import org.springframework.beans.factory.support.DefaultListableBeanFactory;
 import org.springframework.core.MethodParameter;
 import org.springframework.core.annotation.AnnotationUtils;
+import org.springframework.lang.NonNullApi;
 import org.springframework.util.Assert;
 
 /**
@@ -38,6 +39,7 @@ import org.springframework.util.Assert;
  * @author Juergen Hoeller
  * @since 4.0
  */
+@NonNullApi
 public class ContextAnnotationAutowireCandidateResolver extends QualifierAnnotationAutowireCandidateResolver {
 
 	@Override

spring-context/src/main/java/org/springframework/context/annotation/DeferredImportSelector.java

@@ -16,6 +16,8 @@
 
 package org.springframework.context.annotation;
 
+import org.springframework.lang.NonNullApi;
+
 /**
  * A variation of {@link ImportSelector} that runs after all {@code @Configuration} beans
  * have been processed. This type of selector can be particularly useful when the selected
@@ -28,6 +30,7 @@ package org.springframework.context.annotation;
  * @author Phillip Webb
  * @since 4.0
  */
+@NonNullApi
 public interface DeferredImportSelector extends ImportSelector {
 
 }

spring-context/src/main/java/org/springframework/context/annotation/ImportAware.java

@@ -18,6 +18,7 @@ package org.springframework.context.annotation;
 
 import org.springframework.beans.factory.Aware;
 import org.springframework.core.type.AnnotationMetadata;
+import org.springframework.lang.NonNullApi;
 
 /**
  * Interface to be implemented by any @{@link Configuration} class that wishes
@@ -28,6 +29,7 @@ import org.springframework.core.type.AnnotationMetadata;
  * @author Chris Beams
  * @since 3.1
  */
+@NonNullApi
 public interface ImportAware extends Aware {
 
 	/**

spring-context/src/main/java/org/springframework/context/annotation/ImportBeanDefinitionRegistrar.java

@@ -19,6 +19,7 @@ package org.springframework.context.annotation;
 import org.springframework.beans.factory.support.BeanDefinitionRegistry;
 import org.springframework.beans.factory.support.BeanDefinitionRegistryPostProcessor;
 import org.springframework.core.type.AnnotationMetadata;
+import org.springframework.lang.NonNullApi;
 
 /**
  * Interface to be implemented by types that register additional bean definitions when
@@ -47,6 +48,7 @@ import org.springframework.core.type.AnnotationMetadata;
  * @see ImportSelector
  * @see Configuration
  */
+@NonNullApi
 public interface ImportBeanDefinitionRegistrar {
 
 	/**

spring-context/src/main/java/org/springframework/context/annotation/ImportRegistry.java

@@ -17,11 +17,13 @@
 package org.springframework.context.annotation;
 
 import org.springframework.core.type.AnnotationMetadata;
+import org.springframework.lang.NonNullApi;
 
 /**
  * @author Juergen Hoeller
  * @author Phil Webb
  */
+@NonNullApi
 interface ImportRegistry {
 
 	AnnotationMetadata getImportingClassFor(String importedClass);

spring-context/src/main/java/org/springframework/context/annotation/ImportSelector.java

@@ -17,6 +17,7 @@
 package org.springframework.context.annotation;
 
 import org.springframework.core.type.AnnotationMetadata;
+import org.springframework.lang.NonNullApi;
 
 /**
  * Interface to be implemented by types that determine which @{@link Configuration}
@@ -45,6 +46,7 @@ import org.springframework.core.type.AnnotationMetadata;
  * @see ImportBeanDefinitionRegistrar
  * @see Configuration
  */
+@NonNullApi
 public interface ImportSelector {
 
 	/**

spring-context/src/main/java/org/springframework/context/annotation/Jsr330ScopeMetadataResolver.java

@@ -22,6 +22,7 @@ import java.util.Set;
 
 import org.springframework.beans.factory.annotation.AnnotatedBeanDefinition;
 import org.springframework.beans.factory.config.BeanDefinition;
+import org.springframework.lang.NonNullApi;
 
 /**
  * Simple {@link ScopeMetadataResolver} implementation that follows JSR-330 scoping rules:
@@ -39,6 +40,7 @@ import org.springframework.beans.factory.config.BeanDefinition;
  * @see ClassPathBeanDefinitionScanner#setScopeMetadataResolver
  * @see AnnotatedBeanDefinitionReader#setScopeMetadataResolver
  */
+@NonNullApi
 public class Jsr330ScopeMetadataResolver implements ScopeMetadataResolver {
 
 	private final Map<String, String> scopeMap = new HashMap<>();

spring-context/src/main/java/org/springframework/context/annotation/LoadTimeWeavingConfiguration.java

@@ -26,6 +26,7 @@ import org.springframework.context.weaving.DefaultContextLoadTimeWeaver;
 import org.springframework.core.annotation.AnnotationAttributes;
 import org.springframework.core.type.AnnotationMetadata;
 import org.springframework.instrument.classloading.LoadTimeWeaver;
+import org.springframework.lang.NonNullApi;
 import org.springframework.lang.Nullable;
 
 /**
@@ -41,6 +42,7 @@ import org.springframework.lang.Nullable;
  * @see ConfigurableApplicationContext#LOAD_TIME_WEAVER_BEAN_NAME
  */
 @Configuration
+@NonNullApi
 public class LoadTimeWeavingConfiguration implements ImportAware, BeanClassLoaderAware {
 
 	private AnnotationAttributes enableLTW;

spring-context/src/main/java/org/springframework/context/annotation/LoadTimeWeavingConfigurer.java

@@ -17,6 +17,7 @@
 package org.springframework.context.annotation;
 
 import org.springframework.instrument.classloading.LoadTimeWeaver;
+import org.springframework.lang.NonNullApi;
 
 /**
  * Interface to be implemented by
@@ -33,6 +34,7 @@ import org.springframework.instrument.classloading.LoadTimeWeaver;
  * @see LoadTimeWeavingConfiguration
  * @see EnableLoadTimeWeaving
  */
+@NonNullApi
 public interface LoadTimeWeavingConfigurer {
 
 	/**

spring-context/src/main/java/org/springframework/context/annotation/MBeanExportConfiguration.java

@@ -32,6 +32,7 @@ import org.springframework.jmx.export.annotation.AnnotationMBeanExporter;
 import org.springframework.jmx.support.RegistrationPolicy;
 import org.springframework.jmx.support.WebSphereMBeanServerFactoryBean;
 import org.springframework.jndi.JndiLocatorDelegate;
+import org.springframework.lang.NonNullApi;
 import org.springframework.lang.Nullable;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.StringUtils;
@@ -48,6 +49,7 @@ import org.springframework.util.StringUtils;
  * @see EnableMBeanExport
  */
 @Configuration
+@NonNullApi
 public class MBeanExportConfiguration implements ImportAware, EnvironmentAware, BeanFactoryAware {
 
 	private static final String MBEAN_EXPORTER_BEAN_NAME = "mbeanExporter";

spring-context/src/main/java/org/springframework/context/annotation/ParserStrategyUtils.java

@@ -26,6 +26,7 @@ import org.springframework.context.EnvironmentAware;
 import org.springframework.context.ResourceLoaderAware;
 import org.springframework.core.env.Environment;
 import org.springframework.core.io.ResourceLoader;
+import org.springframework.lang.NonNullApi;
 
 /**
  * Common delegate code for the handling of parser strategies, e.g.
@@ -34,6 +35,7 @@ import org.springframework.core.io.ResourceLoader;
  * @author Juergen Hoeller
  * @since 4.3.3
  */
+@NonNullApi
 abstract class ParserStrategyUtils {
 
 	/**

spring-context/src/main/java/org/springframework/context/annotation/ScannedGenericBeanDefinition.java

@@ -22,6 +22,7 @@ import org.springframework.beans.factory.support.GenericBeanDefinition;
 import org.springframework.core.type.AnnotationMetadata;
 import org.springframework.core.type.MethodMetadata;
 import org.springframework.core.type.classreading.MetadataReader;
+import org.springframework.lang.NonNullApi;
 import org.springframework.util.Assert;
 
 /**
@@ -45,6 +46,7 @@ import org.springframework.util.Assert;
  * @see AnnotatedGenericBeanDefinition
  */
 @SuppressWarnings("serial")
+@NonNullApi
 public class ScannedGenericBeanDefinition extends GenericBeanDefinition implements AnnotatedBeanDefinition {
 
 	private final AnnotationMetadata metadata;

spring-context/src/main/java/org/springframework/context/annotation/ScopeMetadata.java

@@ -17,6 +17,7 @@
 package org.springframework.context.annotation;
 
 import org.springframework.beans.factory.config.BeanDefinition;
+import org.springframework.lang.NonNullApi;
 import org.springframework.util.Assert;
 
 /**
@@ -32,6 +33,7 @@ import org.springframework.util.Assert;
  * @see ScopeMetadataResolver
  * @see ScopedProxyMode
  */
+@NonNullApi
 public class ScopeMetadata {
 
 	private String scopeName = BeanDefinition.SCOPE_SINGLETON;

spring-context/src/main/java/org/springframework/context/annotation/ScopeMetadataResolver.java

@@ -17,6 +17,7 @@
 package org.springframework.context.annotation;
 
 import org.springframework.beans.factory.config.BeanDefinition;
+import org.springframework.lang.NonNullApi;
 
 /**
  * Strategy interface for resolving the scope of bean definitions.
@@ -26,6 +27,7 @@ import org.springframework.beans.factory.config.BeanDefinition;
  * @see org.springframework.context.annotation.Scope
  */
 @FunctionalInterface
+@NonNullApi
 public interface ScopeMetadataResolver {
 
 	/**

spring-context/src/main/java/org/springframework/context/annotation/ScopedProxyCreator.java

@@ -19,6 +19,7 @@ package org.springframework.context.annotation;
 import org.springframework.aop.scope.ScopedProxyUtils;
 import org.springframework.beans.factory.config.BeanDefinitionHolder;
 import org.springframework.beans.factory.support.BeanDefinitionRegistry;
+import org.springframework.lang.NonNullApi;
 
 /**
  * Delegate factory class used to just introduce an AOP framework dependency
@@ -28,6 +29,7 @@ import org.springframework.beans.factory.support.BeanDefinitionRegistry;
  * @since 3.0
  * @see org.springframework.aop.scope.ScopedProxyUtils#createScopedProxy
  */
+@NonNullApi
 class ScopedProxyCreator {
 
 	public static BeanDefinitionHolder createScopedProxy(

spring-context/src/main/java/org/springframework/context/annotation/package-info.java

@@ -3,7 +3,4 @@
  * annotations, component-scanning, and Java-based metadata for creating
  * Spring-managed objects.
  */
-@NonNullApi
 package org.springframework.context.annotation;
-
-import org.springframework.lang.NonNullApi;

spring-core/src/main/java/org/springframework/core/env/AbstractEnvironment.java

@@ -27,6 +27,7 @@ import org.apache.commons.logging.LogFactory;
 
 import org.springframework.core.SpringProperties;
 import org.springframework.core.convert.support.ConfigurableConversionService;
+import org.springframework.lang.NonNullApi;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.ObjectUtils;
@@ -51,6 +52,7 @@ import org.springframework.util.StringUtils;
  * @see ConfigurableEnvironment
  * @see StandardEnvironment
  */
+@NonNullApi
 public abstract class AbstractEnvironment implements ConfigurableEnvironment {
 
 	/**

spring-core/src/main/java/org/springframework/core/env/AbstractPropertyResolver.java

@@ -25,6 +25,7 @@ import org.apache.commons.logging.LogFactory;
 import org.springframework.core.convert.ConversionService;
 import org.springframework.core.convert.support.ConfigurableConversionService;
 import org.springframework.core.convert.support.DefaultConversionService;
+import org.springframework.lang.NonNullApi;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
@@ -38,6 +39,7 @@ import org.springframework.util.SystemPropertyUtils;
  * @author Juergen Hoeller
  * @since 3.1
  */
+@NonNullApi
 public abstract class AbstractPropertyResolver implements ConfigurablePropertyResolver {
 
 	protected final Log logger = LogFactory.getLog(getClass());

spring-core/src/main/java/org/springframework/core/env/CommandLineArgs.java

@@ -23,6 +23,7 @@ import java.util.List;
 import java.util.Map;
 import java.util.Set;
 
+import org.springframework.lang.NonNullApi;
 import org.springframework.lang.Nullable;
 
 /**
@@ -33,6 +34,7 @@ import org.springframework.lang.Nullable;
  * @since 3.1
  * @see SimpleCommandLineArgsParser
  */
+@NonNullApi
 class CommandLineArgs {
 
 	private final Map<String, List<String>> optionArgs = new HashMap<>();

spring-core/src/main/java/org/springframework/core/env/CommandLinePropertySource.java

@@ -19,6 +19,7 @@ package org.springframework.core.env;
 import java.util.Collection;
 import java.util.List;
 
+import org.springframework.lang.NonNullApi;
 import org.springframework.lang.Nullable;
 import org.springframework.util.StringUtils;
 
@@ -204,6 +205,7 @@ import org.springframework.util.StringUtils;
  * @see SimpleCommandLinePropertySource
  * @see JOptCommandLinePropertySource
  */
+@NonNullApi
 public abstract class CommandLinePropertySource<T> extends EnumerablePropertySource<T> {
 
 	/** The default name given to {@link CommandLinePropertySource} instances: {@value} */

spring-core/src/main/java/org/springframework/core/env/CompositePropertySource.java

@@ -23,6 +23,7 @@ import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Set;
 
+import org.springframework.lang.NonNullApi;
 import org.springframework.util.StringUtils;
 
 /**
@@ -39,6 +40,7 @@ import org.springframework.util.StringUtils;
  * @author Phillip Webb
  * @since 3.1.1
  */
+@NonNullApi
 public class CompositePropertySource extends EnumerablePropertySource<Object> {
 
 	private final Set<PropertySource<?>> propertySources = new LinkedHashSet<>();

spring-core/src/main/java/org/springframework/core/env/ConfigurableEnvironment.java

@@ -18,6 +18,8 @@ package org.springframework.core.env;
 
 import java.util.Map;
 
+import org.springframework.lang.NonNullApi;
+
 /**
  * Configuration interface to be implemented by most if not all {@link Environment} types.
  * Provides facilities for setting active and default profiles and manipulating underlying
@@ -69,6 +71,7 @@ import java.util.Map;
  * @see StandardEnvironment
  * @see org.springframework.context.ConfigurableApplicationContext#getEnvironment
  */
+@NonNullApi
 public interface ConfigurableEnvironment extends Environment, ConfigurablePropertyResolver {
 
 	/**

spring-core/src/main/java/org/springframework/core/env/ConfigurablePropertyResolver.java

@@ -17,6 +17,7 @@
 package org.springframework.core.env;
 
 import org.springframework.core.convert.support.ConfigurableConversionService;
+import org.springframework.lang.NonNullApi;
 import org.springframework.lang.Nullable;
 
 /**
@@ -28,6 +29,7 @@ import org.springframework.lang.Nullable;
  * @author Chris Beams
  * @since 3.1
  */
+@NonNullApi
 public interface ConfigurablePropertyResolver extends PropertyResolver {
 
 	/**

spring-core/src/main/java/org/springframework/core/env/EnumerablePropertySource.java

@@ -16,6 +16,7 @@
 
 package org.springframework.core.env;
 
+import org.springframework.lang.NonNullApi;
 import org.springframework.util.ObjectUtils;
 
 /**
@@ -41,6 +42,7 @@ import org.springframework.util.ObjectUtils;
  * @author Juergen Hoeller
  * @since 3.1
  */
+@NonNullApi
 public abstract class EnumerablePropertySource<T> extends PropertySource<T> {
 
 	public EnumerablePropertySource(String name, T source) {

spring-core/src/main/java/org/springframework/core/env/Environment.java

@@ -16,6 +16,8 @@
 
 package org.springframework.core.env;
 
+import org.springframework.lang.NonNullApi;
+
 /**
  * Interface representing the environment in which the current application is running.
  * Models two key aspects of the application environment: <em>profiles</em> and
@@ -68,6 +70,7 @@ package org.springframework.core.env;
  * @see org.springframework.context.ConfigurableApplicationContext#setEnvironment
  * @see org.springframework.context.support.AbstractApplicationContext#createEnvironment
  */
+@NonNullApi
 public interface Environment extends PropertyResolver {
 
 	/**

spring-core/src/main/java/org/springframework/core/env/EnvironmentCapable.java

@@ -16,8 +16,6 @@
 
 package org.springframework.core.env;
 
-import org.springframework.lang.Nullable;
-
 /**
  * Interface indicating a component that contains and exposes an {@link Environment} reference.
  *
@@ -46,7 +44,6 @@ public interface EnvironmentCapable {
 	 * Return the {@link Environment} associated with this component
 	 * (may be {@code null} or a default environment).
 	 */
-	@Nullable
 	Environment getEnvironment();
 
 }

spring-core/src/main/java/org/springframework/core/env/JOptCommandLinePropertySource.java

@@ -23,6 +23,8 @@ import java.util.List;
 import joptsimple.OptionSet;
 import joptsimple.OptionSpec;
 
+import org.springframework.lang.NonNullApi;
+
 /**
  * {@link CommandLinePropertySource} implementation backed by a JOpt {@link OptionSet}.
  *
@@ -54,6 +56,7 @@ import joptsimple.OptionSpec;
  * @see joptsimple.OptionParser
  * @see joptsimple.OptionSet
  */
+@NonNullApi
 public class JOptCommandLinePropertySource extends CommandLinePropertySource<OptionSet> {
 
 	/**

spring-core/src/main/java/org/springframework/core/env/MapPropertySource.java

@@ -18,6 +18,7 @@ package org.springframework.core.env;
 
 import java.util.Map;
 
+import org.springframework.lang.NonNullApi;
 import org.springframework.util.StringUtils;
 
 /**
@@ -28,6 +29,7 @@ import org.springframework.util.StringUtils;
  * @since 3.1
  * @see PropertiesPropertySource
  */
+@NonNullApi
 public class MapPropertySource extends EnumerablePropertySource<Map<String, Object>> {
 
 	public MapPropertySource(String name, Map<String, Object> source) {

spring-core/src/main/java/org/springframework/core/env/MissingRequiredPropertiesException.java

@@ -19,6 +19,8 @@ package org.springframework.core.env;
 import java.util.LinkedHashSet;
 import java.util.Set;
 
+import org.springframework.lang.NonNullApi;
+
 /**
  * Exception thrown when required properties are not found.
  *
@@ -29,6 +31,7 @@ import java.util.Set;
  * @see org.springframework.context.support.AbstractApplicationContext#prepareRefresh()
  */
 @SuppressWarnings("serial")
+@NonNullApi
 public class MissingRequiredPropertiesException extends IllegalStateException {
 
 	private final Set<String> missingRequiredProperties = new LinkedHashSet<>();

spring-core/src/main/java/org/springframework/core/env/MutablePropertySources.java

@@ -23,6 +23,7 @@ import java.util.concurrent.CopyOnWriteArrayList;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
+import org.springframework.lang.NonNullApi;
 import org.springframework.lang.Nullable;
 import org.springframework.util.StringUtils;
 
@@ -40,6 +41,7 @@ import org.springframework.util.StringUtils;
  * @since 3.1
  * @see PropertySourcesPropertyResolver
  */
+@NonNullApi
 public class MutablePropertySources implements PropertySources {
 
 	private final Log logger;

spring-core/src/main/java/org/springframework/core/env/PropertiesPropertySource.java

@@ -19,6 +19,8 @@ package org.springframework.core.env;
 import java.util.Map;
 import java.util.Properties;
 
+import org.springframework.lang.NonNullApi;
+
 /**
  * {@link PropertySource} implementation that extracts properties from a
  * {@link java.util.Properties} object.
@@ -33,6 +35,7 @@ import java.util.Properties;
  * @author Juergen Hoeller
  * @since 3.1
  */
+@NonNullApi
 public class PropertiesPropertySource extends MapPropertySource {
 
 	@SuppressWarnings({"unchecked", "rawtypes"})

spring-core/src/main/java/org/springframework/core/env/PropertyResolver.java

@@ -16,6 +16,7 @@
 
 package org.springframework.core.env;
 
+import org.springframework.lang.NonNullApi;
 import org.springframework.lang.Nullable;
 
 /**
@@ -27,6 +28,7 @@ import org.springframework.lang.Nullable;
  * @see Environment
  * @see PropertySourcesPropertyResolver
  */
+@NonNullApi
 public interface PropertyResolver {
 
 	/**

spring-core/src/main/java/org/springframework/core/env/PropertySource.java

@@ -19,6 +19,7 @@ package org.springframework.core.env;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
+import org.springframework.lang.NonNullApi;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.ObjectUtils;
@@ -56,6 +57,7 @@ import org.springframework.util.ObjectUtils;
  * @see MutablePropertySources
  * @see org.springframework.context.annotation.PropertySource
  */
+@NonNullApi
 public abstract class PropertySource<T> {
 
 	protected final Log logger = LogFactory.getLog(getClass());

spring-core/src/main/java/org/springframework/core/env/PropertySources.java

@@ -16,6 +16,7 @@
 
 package org.springframework.core.env;
 
+import org.springframework.lang.NonNullApi;
 import org.springframework.lang.Nullable;
 
 /**
@@ -24,6 +25,7 @@ import org.springframework.lang.Nullable;
  * @author Chris Beams
  * @since 3.1
  */
+@NonNullApi
 public interface PropertySources extends Iterable<PropertySource<?>> {
 
 	/**

spring-core/src/main/java/org/springframework/core/env/PropertySourcesPropertyResolver.java

@@ -16,6 +16,7 @@
 
 package org.springframework.core.env;
 
+import org.springframework.lang.NonNullApi;
 import org.springframework.lang.Nullable;
 
 /**
@@ -29,6 +30,7 @@ import org.springframework.lang.Nullable;
  * @see PropertySources
  * @see AbstractEnvironment
  */
+@NonNullApi
 public class PropertySourcesPropertyResolver extends AbstractPropertyResolver {
 
 	private final PropertySources propertySources;

spring-core/src/main/java/org/springframework/core/env/ReadOnlySystemAttributesMap.java

@@ -21,6 +21,8 @@ import java.util.Collections;
 import java.util.Map;
 import java.util.Set;
 
+import org.springframework.lang.NonNullApi;
+
 /**
  * Read-only {@code Map<String, String>} implementation that is backed by system
  * properties or environment variables.
@@ -35,6 +37,7 @@ import java.util.Set;
  * @author Chris Beams
  * @since 3.0
  */
+@NonNullApi
 abstract class ReadOnlySystemAttributesMap implements Map<String, String> {
 
 	@Override

spring-core/src/main/java/org/springframework/core/env/SimpleCommandLineArgsParser.java

@@ -16,6 +16,8 @@
 
 package org.springframework.core.env;
 
+import org.springframework.lang.NonNullApi;
+
 /**
  * Parses a {@code String[]} of command line arguments in order to populate a
  * {@link CommandLineArgs} object.
@@ -49,6 +51,7 @@ package org.springframework.core.env;
  * @author Chris Beams
  * @since 3.1
  */
+@NonNullApi
 class SimpleCommandLineArgsParser {
 
 	/**

spring-core/src/main/java/org/springframework/core/env/SimpleCommandLinePropertySource.java

@@ -18,6 +18,8 @@ package org.springframework.core.env;
 
 import java.util.List;
 
+import org.springframework.lang.NonNullApi;
+
 /**
  * {@link CommandLinePropertySource} implementation backed by a simple String array.
  *
@@ -75,6 +77,7 @@ import java.util.List;
  * @see CommandLinePropertySource
  * @see JOptCommandLinePropertySource
  */
+@NonNullApi
 public class SimpleCommandLinePropertySource extends CommandLinePropertySource<CommandLineArgs> {
 
 	/**

spring-core/src/main/java/org/springframework/core/env/StandardEnvironment.java

@@ -16,6 +16,8 @@
 
 package org.springframework.core.env;
 
+import org.springframework.lang.NonNullApi;
+
 /**
  * {@link Environment} implementation suitable for use in 'standard' (i.e. non-web)
  * applications.
@@ -51,6 +53,7 @@ package org.springframework.core.env;
  * @see SystemEnvironmentPropertySource
  * @see org.springframework.web.context.support.StandardServletEnvironment
  */
+@NonNullApi
 public class StandardEnvironment extends AbstractEnvironment {
 
 	/** System environment property source name: {@value} */

spring-core/src/main/java/org/springframework/core/env/SystemEnvironmentPropertySource.java

@@ -18,6 +18,7 @@ package org.springframework.core.env;
 
 import java.util.Map;
 
+import org.springframework.lang.NonNullApi;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 
@@ -63,6 +64,7 @@ import org.springframework.util.Assert;
  * @see AbstractEnvironment#getSystemEnvironment()
  * @see AbstractEnvironment#ACTIVE_PROFILES_PROPERTY_NAME
  */
+@NonNullApi
 public class SystemEnvironmentPropertySource extends MapPropertySource {
 
 	/**

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

@@ -2,7 +2,4 @@
  * Spring's environment abstraction consisting of bean definition
  * profile and hierarchical property source support.
  */
-@NonNullApi
 package org.springframework.core.env;
-
-import org.springframework.lang.NonNullApi;

spring-core/src/main/java/org/springframework/lang/NonNullApi.java

@@ -23,7 +23,7 @@ import javax.annotation.meta.TypeQualifierDefault;
  */
 @Documented
 @Nonnull
-@Target(ElementType.PACKAGE)
+@Target({ElementType.PACKAGE, ElementType.TYPE})
 @TypeQualifierDefault({ElementType.METHOD, ElementType.PARAMETER})
 @Retention(RetentionPolicy.RUNTIME)
 public @interface NonNullApi {