Make getters and setters null-safety consistent

This commit ensure that null-safety is consistent between
getters and setters in order to be able to provide beans
with properties with a common type when type safety is
taken in account like with Kotlin.

It also add a few missing property level @Nullable
annotations.

Issue: SPR-15792

spring-aop/src/main/java/org/springframework/aop/aspectj/AspectJExpressionPointcutAdvisor.java

@@ -34,7 +34,7 @@ public class AspectJExpressionPointcutAdvisor extends AbstractGenericPointcutAdv
 	private final AspectJExpressionPointcut pointcut = new AspectJExpressionPointcut();
 
 
-	public void setExpression(String expression) {
+	public void setExpression(@Nullable String expression) {
 		this.pointcut.setExpression(expression);
 	}
 
@@ -43,7 +43,7 @@ public class AspectJExpressionPointcutAdvisor extends AbstractGenericPointcutAdv
 		return this.pointcut.getExpression();
 	}
 
-	public void setLocation(String location) {
+	public void setLocation(@Nullable String location) {
 		this.pointcut.setLocation(location);
 	}
 

spring-aop/src/main/java/org/springframework/aop/framework/autoproxy/AbstractAutoProxyCreator.java

@@ -203,7 +203,7 @@ public abstract class AbstractAutoProxyCreator extends ProxyProcessorSupport
 	}
 
 	@Override
-	public void setBeanFactory(BeanFactory beanFactory) {
+	public void setBeanFactory(@Nullable BeanFactory beanFactory) {
 		this.beanFactory = beanFactory;
 	}
 

spring-aop/src/main/java/org/springframework/aop/framework/autoproxy/DefaultAdvisorAutoProxyCreator.java

@@ -70,7 +70,7 @@ public class DefaultAdvisorAutoProxyCreator extends AbstractAdvisorAutoProxyCrea
 	 * references. Default value is the bean name of this object + a dot.
 	 * @param advisorBeanNamePrefix the exclusion prefix
 	 */
-	public void setAdvisorBeanNamePrefix(String advisorBeanNamePrefix) {
+	public void setAdvisorBeanNamePrefix(@Nullable String advisorBeanNamePrefix) {
 		this.advisorBeanNamePrefix = advisorBeanNamePrefix;
 	}
 

spring-aop/src/main/java/org/springframework/aop/support/AbstractBeanFactoryPointcutAdvisor.java

@@ -63,7 +63,7 @@ public abstract class AbstractBeanFactoryPointcutAdvisor extends AbstractPointcu
 	 * of the advisor.
 	 * @see #getAdvice()
 	 */
-	public void setAdviceBeanName(String adviceBeanName) {
+	public void setAdviceBeanName(@Nullable String adviceBeanName) {
 		this.adviceBeanName = adviceBeanName;
 	}
 

spring-aop/src/main/java/org/springframework/aop/support/AbstractExpressionPointcut.java

@@ -43,7 +43,7 @@ public abstract class AbstractExpressionPointcut implements ExpressionPointcut,
 	/**
 	 * Set the location for debugging.
 	 */
-	public void setLocation(String location) {
+	public void setLocation(@Nullable String location) {
 		this.location = location;
 	}
 
@@ -58,7 +58,7 @@ public abstract class AbstractExpressionPointcut implements ExpressionPointcut,
 		return this.location;
 	}
 
-	public void setExpression(String expression) {
+	public void setExpression(@Nullable String expression) {
 		this.expression = expression;
 		try {
 			onSetExpression(expression);
@@ -82,7 +82,7 @@ public abstract class AbstractExpressionPointcut implements ExpressionPointcut,
 	 * @throws IllegalArgumentException if the expression is invalid
 	 * @see #setExpression
 	 */
-	protected void onSetExpression(String expression) throws IllegalArgumentException {
+	protected void onSetExpression(@Nullable String expression) throws IllegalArgumentException {
 	}
 
 	/**

spring-beans/src/main/java/org/springframework/beans/ExtendedBeanInfo.java

@@ -292,7 +292,7 @@ class ExtendedBeanInfo implements BeanInfo {
 		}
 
 		@Override
-		public void setReadMethod(Method readMethod) {
+		public void setReadMethod(@Nullable Method readMethod) {
 			this.readMethod = readMethod;
 		}
 
@@ -303,7 +303,7 @@ class ExtendedBeanInfo implements BeanInfo {
 		}
 
 		@Override
-		public void setWriteMethod(Method writeMethod) {
+		public void setWriteMethod(@Nullable Method writeMethod) {
 			this.writeMethod = writeMethod;
 		}
 
@@ -327,7 +327,7 @@ class ExtendedBeanInfo implements BeanInfo {
 		}
 
 		@Override
-		public void setPropertyEditorClass(Class<?> propertyEditorClass) {
+		public void setPropertyEditorClass(@Nullable Class<?> propertyEditorClass) {
 			this.propertyEditorClass = propertyEditorClass;
 		}
 
@@ -399,7 +399,7 @@ class ExtendedBeanInfo implements BeanInfo {
 		}
 
 		@Override
-		public void setReadMethod(Method readMethod) {
+		public void setReadMethod(@Nullable Method readMethod) {
 			this.readMethod = readMethod;
 		}
 
@@ -410,7 +410,7 @@ class ExtendedBeanInfo implements BeanInfo {
 		}
 
 		@Override
-		public void setWriteMethod(Method writeMethod) {
+		public void setWriteMethod(@Nullable Method writeMethod) {
 			this.writeMethod = writeMethod;
 		}
 
@@ -434,7 +434,7 @@ class ExtendedBeanInfo implements BeanInfo {
 		}
 
 		@Override
-		public void setIndexedReadMethod(Method indexedReadMethod) throws IntrospectionException {
+		public void setIndexedReadMethod(@Nullable Method indexedReadMethod) throws IntrospectionException {
 			this.indexedReadMethod = indexedReadMethod;
 		}
 
@@ -445,7 +445,7 @@ class ExtendedBeanInfo implements BeanInfo {
 		}
 
 		@Override
-		public void setIndexedWriteMethod(Method indexedWriteMethod) throws IntrospectionException {
+		public void setIndexedWriteMethod(@Nullable Method indexedWriteMethod) throws IntrospectionException {
 			this.indexedWriteMethod = indexedWriteMethod;
 		}
 
@@ -470,7 +470,7 @@ class ExtendedBeanInfo implements BeanInfo {
 		}
 
 		@Override
-		public void setPropertyEditorClass(Class<?> propertyEditorClass) {
+		public void setPropertyEditorClass(@Nullable Class<?> propertyEditorClass) {
 			this.propertyEditorClass = propertyEditorClass;
 		}
 

spring-beans/src/main/java/org/springframework/beans/factory/config/AbstractFactoryBean.java

@@ -101,7 +101,7 @@ public abstract class AbstractFactoryBean<T>
 	}
 
 	@Override
-	public void setBeanFactory(BeanFactory beanFactory) {
+	public void setBeanFactory(@Nullable BeanFactory beanFactory) {
 		this.beanFactory = beanFactory;
 	}
 

spring-beans/src/main/java/org/springframework/beans/factory/config/BeanDefinition.java

@@ -148,7 +148,7 @@ public interface BeanDefinition extends AttributeAccessor, BeanMetadataElement {
 	 * Set the names of the beans that this bean depends on being initialized.
 	 * The bean factory will guarantee that these beans get initialized first.
 	 */
-	void setDependsOn(String... dependsOn);
+	void setDependsOn(@Nullable String... dependsOn);
 
 	/**
 	 * Return the bean names that this bean depends on.

spring-beans/src/main/java/org/springframework/beans/factory/config/ConstructorArgumentValues.java

@@ -554,8 +554,8 @@ public class ConstructorArgumentValues {
 		 * Set the converted value of the constructor argument,
 		 * after processed type conversion.
 		 */
-		public synchronized void setConvertedValue(Object value) {
-			this.converted = true;
+		public synchronized void setConvertedValue(@Nullable Object value) {
+			this.converted = (value != null);
 			this.convertedValue = value;
 		}
 

spring-beans/src/main/java/org/springframework/beans/factory/config/FieldRetrievingFactoryBean.java

@@ -87,7 +87,7 @@ public class FieldRetrievingFactoryBean
 	 * @see #setTargetObject
 	 * @see #setTargetField
 	 */
-	public void setTargetClass(Class<?> targetClass) {
+	public void setTargetClass(@Nullable Class<?> targetClass) {
 		this.targetClass = targetClass;
 	}
 
@@ -106,7 +106,7 @@ public class FieldRetrievingFactoryBean
 	 * @see #setTargetClass
 	 * @see #setTargetField
 	 */
-	public void setTargetObject(Object targetObject) {
+	public void setTargetObject(@Nullable Object targetObject) {
 		this.targetObject = targetObject;
 	}
 
@@ -125,7 +125,7 @@ public class FieldRetrievingFactoryBean
 	 * @see #setTargetClass
 	 * @see #setTargetObject
 	 */
-	public void setTargetField(String targetField) {
+	public void setTargetField(@Nullable String targetField) {
 		this.targetField = StringUtils.trimAllWhitespace(targetField);
 	}
 

spring-beans/src/main/java/org/springframework/beans/factory/config/TypedStringValue.java

@@ -126,8 +126,7 @@ public class TypedStringValue implements BeanMetadataElement {
 	/**
 	 * Specify the type to convert to.
 	 */
-	public void setTargetTypeName(String targetTypeName) {
-		Assert.notNull(targetTypeName, "'targetTypeName' must not be null");
+	public void setTargetTypeName(@Nullable String targetTypeName) {
 		this.targetType = targetTypeName;
 	}
 

spring-beans/src/main/java/org/springframework/beans/factory/serviceloader/AbstractServiceLoaderBasedFactoryBean.java

@@ -45,7 +45,7 @@ public abstract class AbstractServiceLoaderBasedFactoryBean extends AbstractFact
 	/**
 	 * Specify the desired service type (typically the service's public API).
 	 */
-	public void setServiceType(Class<?> serviceType) {
+	public void setServiceType(@Nullable Class<?> serviceType) {
 		this.serviceType = serviceType;
 	}
 

spring-beans/src/main/java/org/springframework/beans/factory/support/AbstractBeanDefinitionReader.java

@@ -122,7 +122,7 @@ public abstract class AbstractBeanDefinitionReader implements EnvironmentCapable
 	 * @see org.springframework.core.io.support.ResourcePatternResolver
 	 * @see org.springframework.core.io.support.PathMatchingResourcePatternResolver
 	 */
-	public void setResourceLoader(ResourceLoader resourceLoader) {
+	public void setResourceLoader(@Nullable ResourceLoader resourceLoader) {
 		this.resourceLoader = resourceLoader;
 	}
 

spring-beans/src/main/java/org/springframework/beans/factory/support/DefaultListableBeanFactory.java

@@ -268,7 +268,7 @@ public class DefaultListableBeanFactory extends AbstractAutowireCapableBeanFacto
 	 * @see org.springframework.core.OrderComparator
 	 * @see org.springframework.core.annotation.AnnotationAwareOrderComparator
 	 */
-	public void setDependencyComparator(Comparator<Object> dependencyComparator) {
+	public void setDependencyComparator(@Nullable Comparator<Object> dependencyComparator) {
 		this.dependencyComparator = dependencyComparator;
 	}
 

spring-beans/src/main/java/org/springframework/beans/factory/support/ManagedMap.java

@@ -71,7 +71,7 @@ public class ManagedMap<K, V> extends LinkedHashMap<K, V> implements Mergeable,
 	/**
 	 * Set the default key type name (class name) to be used for this map.
 	 */
-	public void setKeyTypeName(String keyTypeName) {
+	public void setKeyTypeName(@Nullable String keyTypeName) {
 		this.keyTypeName = keyTypeName;
 	}
 
@@ -86,7 +86,7 @@ public class ManagedMap<K, V> extends LinkedHashMap<K, V> implements Mergeable,
 	/**
 	 * Set the default value type name (class name) to be used for this map.
 	 */
-	public void setValueTypeName(String valueTypeName) {
+	public void setValueTypeName(@Nullable String valueTypeName) {
 		this.valueTypeName = valueTypeName;
 	}
 

spring-beans/src/main/java/org/springframework/beans/factory/support/ManagedSet.java

@@ -68,7 +68,7 @@ public class ManagedSet<E> extends LinkedHashSet<E> implements Mergeable, BeanMe
 	/**
 	 * Set the default element type name (class name) to be used for this set.
 	 */
-	public void setElementTypeName(String elementTypeName) {
+	public void setElementTypeName(@Nullable String elementTypeName) {
 		this.elementTypeName = elementTypeName;
 	}
 

spring-beans/src/main/java/org/springframework/beans/factory/support/RootBeanDefinition.java

@@ -257,7 +257,7 @@ public class RootBeanDefinition extends AbstractBeanDefinition {
 	/**
 	 * Register a target definition that is being decorated by this bean definition.
 	 */
-	public void setDecoratedDefinition(BeanDefinitionHolder decoratedDefinition) {
+	public void setDecoratedDefinition(@Nullable BeanDefinitionHolder decoratedDefinition) {
 		this.decoratedDefinition = decoratedDefinition;
 	}
 
@@ -276,7 +276,7 @@ public class RootBeanDefinition extends AbstractBeanDefinition {
 	 * @see #setTargetType(ResolvableType)
 	 * @see #getResolvedFactoryMethod()
 	 */
-	public void setQualifiedElement(AnnotatedElement qualifiedElement) {
+	public void setQualifiedElement(@Nullable AnnotatedElement qualifiedElement) {
 		this.qualifiedElement = qualifiedElement;
 	}
 

spring-beans/src/main/java/org/springframework/beans/support/ArgumentConvertingMethodInvoker.java

@@ -55,9 +55,9 @@ public class ArgumentConvertingMethodInvoker extends MethodInvoker {
 	 * @see org.springframework.beans.SimpleTypeConverter
 	 * @see org.springframework.beans.BeanWrapperImpl
 	 */
-	public void setTypeConverter(TypeConverter typeConverter) {
+	public void setTypeConverter(@Nullable TypeConverter typeConverter) {
 		this.typeConverter = typeConverter;
-		this.useDefaultConverter = false;
+		this.useDefaultConverter = (typeConverter == null);
 	}
 
 	/**

spring-context-support/src/main/java/org/springframework/cache/ehcache/EhCacheCacheManager.java

@@ -37,6 +37,7 @@ import org.springframework.util.Assert;
  */
 public class EhCacheCacheManager extends AbstractTransactionSupportingCacheManager {
 
+	@Nullable
 	private net.sf.ehcache.CacheManager cacheManager;
 
 
@@ -59,7 +60,7 @@ public class EhCacheCacheManager extends AbstractTransactionSupportingCacheManag
 	/**
 	 * Set the backing EhCache {@link net.sf.ehcache.CacheManager}.
 	 */
-	public void setCacheManager(net.sf.ehcache.CacheManager cacheManager) {
+	public void setCacheManager(@Nullable net.sf.ehcache.CacheManager cacheManager) {
 		this.cacheManager = cacheManager;
 	}
 

spring-context-support/src/main/java/org/springframework/cache/jcache/JCacheCacheManager.java

@@ -38,6 +38,7 @@ import org.springframework.util.Assert;
  */
 public class JCacheCacheManager extends AbstractTransactionSupportingCacheManager {
 
+	@Nullable
 	private javax.cache.CacheManager cacheManager;
 
 	private boolean allowNullValues = true;
@@ -62,7 +63,7 @@ public class JCacheCacheManager extends AbstractTransactionSupportingCacheManage
 	/**
 	 * Set the backing JCache {@link javax.cache.CacheManager}.
 	 */
-	public void setCacheManager(javax.cache.CacheManager cacheManager) {
+	public void setCacheManager(@Nullable javax.cache.CacheManager cacheManager) {
 		this.cacheManager = cacheManager;
 	}
 

spring-context-support/src/main/java/org/springframework/cache/jcache/interceptor/DefaultJCacheOperationSource.java

@@ -63,7 +63,7 @@ public class DefaultJCacheOperationSource extends AnnotationJCacheOperationSourc
 	 * Set the default {@link CacheManager} to use to lookup cache by name. Only mandatory
 	 * if the {@linkplain CacheResolver cache resolvers} have not been set.
 	 */
-	public void setCacheManager(CacheManager cacheManager) {
+	public void setCacheManager(@Nullable CacheManager cacheManager) {
 		this.cacheManager = cacheManager;
 	}
 
@@ -79,7 +79,7 @@ public class DefaultJCacheOperationSource extends AnnotationJCacheOperationSourc
 	 * Set the {@link CacheResolver} to resolve regular caches. If none is set, a default
 	 * implementation using the specified cache manager will be used.
 	 */
-	public void setCacheResolver(CacheResolver cacheResolver) {
+	public void setCacheResolver(@Nullable CacheResolver cacheResolver) {
 		this.cacheResolver = cacheResolver;
 	}
 
@@ -95,7 +95,7 @@ public class DefaultJCacheOperationSource extends AnnotationJCacheOperationSourc
 	 * Set the {@link CacheResolver} to resolve exception caches. If none is set, a default
 	 * implementation using the specified cache manager will be used.
 	 */
-	public void setExceptionCacheResolver(CacheResolver exceptionCacheResolver) {
+	public void setExceptionCacheResolver(@Nullable CacheResolver exceptionCacheResolver) {
 		this.exceptionCacheResolver = exceptionCacheResolver;
 	}
 
@@ -112,7 +112,7 @@ public class DefaultJCacheOperationSource extends AnnotationJCacheOperationSourc
 	 * honoring the JSR-107 {@link javax.cache.annotation.CacheKey} and
 	 * {@link javax.cache.annotation.CacheValue} will be used.
 	 */
-	public void setKeyGenerator(KeyGenerator keyGenerator) {
+	public void setKeyGenerator(@Nullable KeyGenerator keyGenerator) {
 		this.keyGenerator = keyGenerator;
 	}
 

spring-context-support/src/main/java/org/springframework/mail/SimpleMailMessage.java

@@ -98,7 +98,7 @@ public class SimpleMailMessage implements MailMessage, Serializable {
 
 
 	@Override
-	public void setFrom(String from) {
+	public void setFrom(@Nullable String from) {
 		this.from = from;
 	}
 
@@ -108,7 +108,7 @@ public class SimpleMailMessage implements MailMessage, Serializable {
 	}
 
 	@Override
-	public void setReplyTo(String replyTo) {
+	public void setReplyTo(@Nullable String replyTo) {
 		this.replyTo = replyTo;
 	}
 
@@ -118,12 +118,12 @@ public class SimpleMailMessage implements MailMessage, Serializable {
 	}
 
 	@Override
-	public void setTo(String to) {
+	public void setTo(@Nullable String to) {
 		this.to = new String[] {to};
 	}
 
 	@Override
-	public void setTo(String[] to) {
+	public void setTo(@Nullable String[] to) {
 		this.to = to;
 	}
 
@@ -133,12 +133,12 @@ public class SimpleMailMessage implements MailMessage, Serializable {
 	}
 
 	@Override
-	public void setCc(String cc) {
+	public void setCc(@Nullable String cc) {
 		this.cc = new String[] {cc};
 	}
 
 	@Override
-	public void setCc(String[] cc) {
+	public void setCc(@Nullable String[] cc) {
 		this.cc = cc;
 	}
 
@@ -148,12 +148,12 @@ public class SimpleMailMessage implements MailMessage, Serializable {
 	}
 
 	@Override
-	public void setBcc(String bcc) {
+	public void setBcc(@Nullable String bcc) {
 		this.bcc = new String[] {bcc};
 	}
 
 	@Override
-	public void setBcc(String[] bcc) {
+	public void setBcc(@Nullable String[] bcc) {
 		this.bcc = bcc;
 	}
 
@@ -163,7 +163,7 @@ public class SimpleMailMessage implements MailMessage, Serializable {
 	}
 
 	@Override
-	public void setSentDate(Date sentDate) {
+	public void setSentDate(@Nullable Date sentDate) {
 		this.sentDate = sentDate;
 	}
 
@@ -173,7 +173,7 @@ public class SimpleMailMessage implements MailMessage, Serializable {
 	}
 
 	@Override
-	public void setSubject(String subject) {
+	public void setSubject(@Nullable String subject) {
 		this.subject = subject;
 	}
 
@@ -183,7 +183,7 @@ public class SimpleMailMessage implements MailMessage, Serializable {
 	}
 
 	@Override
-	public void setText(String text) {
+	public void setText(@Nullable String text) {
 		this.text = text;
 	}
 

spring-context-support/src/main/java/org/springframework/mail/javamail/JavaMailSenderImpl.java

@@ -99,6 +99,7 @@ public class JavaMailSenderImpl implements JavaMailSender {
 	@Nullable
 	private String defaultEncoding;
 
+	@Nullable
 	private FileTypeMap defaultFileTypeMap;
 
 
@@ -165,7 +166,7 @@ public class JavaMailSenderImpl implements JavaMailSender {
 	/**
 	 * Set the mail protocol. Default is "smtp".
 	 */
-	public void setProtocol(String protocol) {
+	public void setProtocol(@Nullable String protocol) {
 		this.protocol = protocol;
 	}
 
@@ -181,7 +182,7 @@ public class JavaMailSenderImpl implements JavaMailSender {
 	 * Set the mail server host, typically an SMTP host.
 	 * <p>Default is the default host of the underlying JavaMail Session.
 	 */
-	public void setHost(String host) {
+	public void setHost(@Nullable String host) {
 		this.host = host;
 	}
 
@@ -220,7 +221,7 @@ public class JavaMailSenderImpl implements JavaMailSender {
 	 * @see #setSession
 	 * @see #setPassword
 	 */
-	public void setUsername(String username) {
+	public void setUsername(@Nullable String username) {
 		this.username = username;
 	}
 
@@ -243,7 +244,7 @@ public class JavaMailSenderImpl implements JavaMailSender {
 	 * @see #setSession
 	 * @see #setUsername
 	 */
-	public void setPassword(String password) {
+	public void setPassword(@Nullable String password) {
 		this.password = password;
 	}
 
@@ -260,7 +261,7 @@ public class JavaMailSenderImpl implements JavaMailSender {
 	 * created by this instance.
 	 * <p>Such an encoding will be auto-detected by {@link MimeMessageHelper}.
 	 */
-	public void setDefaultEncoding(String defaultEncoding) {
+	public void setDefaultEncoding(@Nullable String defaultEncoding) {
 		this.defaultEncoding = defaultEncoding;
 	}
 
@@ -286,7 +287,7 @@ public class JavaMailSenderImpl implements JavaMailSender {
 	 * {@code mime.types} file contained in the Spring jar).
 	 * @see MimeMessageHelper#setFileTypeMap
 	 */
-	public void setDefaultFileTypeMap(FileTypeMap defaultFileTypeMap) {
+	public void setDefaultFileTypeMap(@Nullable FileTypeMap defaultFileTypeMap) {
 		this.defaultFileTypeMap = defaultFileTypeMap;
 	}
 

spring-context/src/main/java/org/springframework/cache/interceptor/CacheAspectSupport.java

@@ -86,12 +86,15 @@ public abstract class CacheAspectSupport extends AbstractCacheInvoker
 
 	private final CacheOperationExpressionEvaluator evaluator = new CacheOperationExpressionEvaluator();
 
+	@Nullable
 	private CacheOperationSource cacheOperationSource;
 
 	private KeyGenerator keyGenerator = new SimpleKeyGenerator();
 
+	@Nullable
 	private CacheResolver cacheResolver;
 
+	@Nullable
 	private BeanFactory beanFactory;
 
 	private boolean initialized = false;
@@ -150,8 +153,7 @@ public abstract class CacheAspectSupport extends AbstractCacheInvoker
 	 * @see #setCacheManager(org.springframework.cache.CacheManager)
 	 * @see SimpleCacheResolver
 	 */
-	public void setCacheResolver(CacheResolver cacheResolver) {
-		Assert.notNull(cacheResolver, "CacheResolver must not be null");
+	public void setCacheResolver(@Nullable CacheResolver cacheResolver) {
 		this.cacheResolver = cacheResolver;
 	}
 

spring-context/src/main/java/org/springframework/context/support/AbstractMessageSource.java

@@ -90,7 +90,7 @@ public abstract class AbstractMessageSource extends MessageSourceSupport impleme
 	 * <p>May also link to an externally defined Properties object, e.g. defined
 	 * through a {@link org.springframework.beans.factory.config.PropertiesFactoryBean}.
 	 */
-	public void setCommonMessages(Properties commonMessages) {
+	public void setCommonMessages(@Nullable Properties commonMessages) {
 		this.commonMessages = commonMessages;
 	}
 

spring-context/src/main/java/org/springframework/context/support/AbstractResourceBasedMessageSource.java

@@ -119,7 +119,7 @@ public abstract class AbstractResourceBasedMessageSource extends AbstractMessage
 	 * <p>Only applies to classic properties files, not to XML files.
 	 * @param defaultEncoding the default charset
 	 */
-	public void setDefaultEncoding(String defaultEncoding) {
+	public void setDefaultEncoding(@Nullable String defaultEncoding) {
 		this.defaultEncoding = defaultEncoding;
 	}
 

spring-context/src/main/java/org/springframework/ejb/access/LocalStatelessSessionProxyFactoryBean.java

@@ -70,7 +70,7 @@ public class LocalStatelessSessionProxyFactoryBean extends LocalSlsbInvokerInter
 	 * Using a business methods interface is a best practice when implementing EJBs.
 	 * @param businessInterface set the business interface of the EJB
 	 */
-	public void setBusinessInterface(Class<?> businessInterface) {
+	public void setBusinessInterface(@Nullable Class<?> businessInterface) {
 		this.businessInterface = businessInterface;
 	}
 

spring-context/src/main/java/org/springframework/ejb/access/SimpleRemoteStatelessSessionProxyFactoryBean.java

@@ -84,7 +84,7 @@ public class SimpleRemoteStatelessSessionProxyFactoryBean extends SimpleRemoteSl
 	 * converted to Spring's generic RemoteAccessException.
 	 * @param businessInterface the business interface of the EJB
 	 */
-	public void setBusinessInterface(Class<?> businessInterface) {
+	public void setBusinessInterface(@Nullable Class<?> businessInterface) {
 		this.businessInterface = businessInterface;
 	}
 

spring-context/src/main/java/org/springframework/format/datetime/joda/JodaTimeContext.java

@@ -49,7 +49,7 @@ public class JodaTimeContext {
 	/**
 	 * Set the user's chronology (calendar system).
 	 */
-	public void setChronology(Chronology chronology) {
+	public void setChronology(@Nullable Chronology chronology) {
 		this.chronology = chronology;
 	}
 
@@ -69,7 +69,7 @@ public class JodaTimeContext {
 	 * @see org.springframework.context.i18n.LocaleContextHolder#getTimeZone()
 	 * @see org.springframework.context.i18n.LocaleContextHolder#setLocaleContext
 	 */
-	public void setTimeZone(DateTimeZone timeZone) {
+	public void setTimeZone(@Nullable DateTimeZone timeZone) {
 		this.timeZone = timeZone;
 	}
 

spring-context/src/main/java/org/springframework/format/datetime/standard/DateTimeContext.java

@@ -47,7 +47,7 @@ public class DateTimeContext {
 	/**
 	 * Set the user's chronology (calendar system).
 	 */
-	public void setChronology(Chronology chronology) {
+	public void setChronology(@Nullable Chronology chronology) {
 		this.chronology = chronology;
 	}
 
@@ -67,7 +67,7 @@ public class DateTimeContext {
 	 * @see org.springframework.context.i18n.LocaleContextHolder#getTimeZone()
 	 * @see org.springframework.context.i18n.LocaleContextHolder#setLocaleContext
 	 */
-	public void setTimeZone(ZoneId timeZone) {
+	public void setTimeZone(@Nullable ZoneId timeZone) {
 		this.timeZone = timeZone;
 	}
 

spring-context/src/main/java/org/springframework/jmx/access/MBeanClientInterceptor.java

@@ -158,7 +158,7 @@ public class MBeanClientInterceptor
 	 * Specify the environment for the JMX connector.
 	 * @see javax.management.remote.JMXConnectorFactory#connect(javax.management.remote.JMXServiceURL, java.util.Map)
 	 */
-	public void setEnvironment(Map<String, ?> environment) {
+	public void setEnvironment(@Nullable Map<String, ?> environment) {
 		this.environment = environment;
 	}
 
@@ -229,7 +229,7 @@ public class MBeanClientInterceptor
 	 * setters and getters for MBean attributes and conventional Java methods
 	 * for MBean operations.
 	 */
-	public void setManagementInterface(Class<?> managementInterface) {
+	public void setManagementInterface(@Nullable Class<?> managementInterface) {
 		this.managementInterface = managementInterface;
 	}
 

spring-context/src/main/java/org/springframework/jmx/access/NotificationListenerRegistrar.java

@@ -82,7 +82,7 @@ public class NotificationListenerRegistrar extends NotificationListenerHolder
 	 * Specify the environment for the JMX connector.
 	 * @see javax.management.remote.JMXConnectorFactory#connect(javax.management.remote.JMXServiceURL, java.util.Map)
 	 */
-	public void setEnvironment(Map<String, ?> environment) {
+	public void setEnvironment(@Nullable Map<String, ?> environment) {
 		this.environment = environment;
 	}
 

spring-context/src/main/java/org/springframework/jmx/export/assembler/AbstractReflectiveMBeanInfoAssembler.java

@@ -172,6 +172,7 @@ public abstract class AbstractReflectiveMBeanInfoAssembler extends AbstractMBean
 	/**
 	 * Default value for the JMX field "currencyTimeLimit".
 	 */
+	@Nullable
 	private Integer defaultCurrencyTimeLimit;
 
 	/**
@@ -181,6 +182,7 @@ public abstract class AbstractReflectiveMBeanInfoAssembler extends AbstractMBean
 
 	private boolean exposeClassDescriptor = false;
 
+	@Nullable
 	private ParameterNameDiscoverer parameterNameDiscoverer = new DefaultParameterNameDiscoverer();
 
 
@@ -204,7 +206,7 @@ public abstract class AbstractReflectiveMBeanInfoAssembler extends AbstractMBean
 	 * @see org.springframework.jmx.export.metadata.AbstractJmxAttribute#setCurrencyTimeLimit
 	 * @see #applyCurrencyTimeLimit(javax.management.Descriptor, int)
 	 */
-	public void setDefaultCurrencyTimeLimit(Integer defaultCurrencyTimeLimit) {
+	public void setDefaultCurrencyTimeLimit(@Nullable Integer defaultCurrencyTimeLimit) {
 		this.defaultCurrencyTimeLimit = defaultCurrencyTimeLimit;
 	}
 
@@ -266,7 +268,7 @@ public abstract class AbstractReflectiveMBeanInfoAssembler extends AbstractMBean
 	 * names if needed (e.g. for parameter names of MBean operation methods).
 	 * <p>Default is a {@link DefaultParameterNameDiscoverer}.
 	 */
-	public void setParameterNameDiscoverer(ParameterNameDiscoverer parameterNameDiscoverer) {
+	public void setParameterNameDiscoverer(@Nullable ParameterNameDiscoverer parameterNameDiscoverer) {
 		this.parameterNameDiscoverer = parameterNameDiscoverer;
 	}
 

spring-context/src/main/java/org/springframework/jmx/export/metadata/ManagedNotification.java

@@ -27,10 +27,13 @@ import org.springframework.util.StringUtils;
  */
 public class ManagedNotification {
 
+	@Nullable
 	private String[] notificationTypes;
 
+	@Nullable
 	private String name;
 
+	@Nullable
 	private String description;
 
 
@@ -45,7 +48,7 @@ public class ManagedNotification {
 	/**
 	 * Set a list of notification types.
 	 */
-	public void setNotificationTypes(String... notificationTypes) {
+	public void setNotificationTypes(@Nullable String... notificationTypes) {
 		this.notificationTypes = notificationTypes;
 	}
 
@@ -60,13 +63,14 @@ public class ManagedNotification {
 	/**
 	 * Set the name of this notification.
 	 */
-	public void setName(String name) {
+	public void setName(@Nullable String name) {
 		this.name = name;
 	}
 
 	/**
 	 * Return the name of this notification.
 	 */
+	@Nullable
 	public String getName() {
 		return this.name;
 	}
@@ -74,7 +78,7 @@ public class ManagedNotification {
 	/**
 	 * Set a description for this notification.
 	 */
-	public void setDescription(String description) {
+	public void setDescription(@Nullable String description) {
 		this.description = description;
 	}
 

spring-context/src/main/java/org/springframework/jmx/support/MBeanRegistrationSupport.java

@@ -96,7 +96,7 @@ public class MBeanRegistrationSupport {
 	 * be registered. The {@code MBeanExporter} will attempt to locate an
 	 * existing {@code MBeanServer} if none is supplied.
 	 */
-	public void setServer(MBeanServer server) {
+	public void setServer(@Nullable MBeanServer server) {
 		this.server = server;
 	}
 

spring-context/src/main/java/org/springframework/jndi/JndiObjectLocator.java

@@ -62,7 +62,7 @@ public abstract class JndiObjectLocator extends JndiLocatorSupport implements In
 	 * @param jndiName the JNDI name to look up
 	 * @see #setResourceRef
 	 */
-	public void setJndiName(String jndiName) {
+	public void setJndiName(@Nullable String jndiName) {
 		this.jndiName = jndiName;
 	}
 

spring-context/src/main/java/org/springframework/remoting/support/RemoteInvocation.java

@@ -181,7 +181,7 @@ public class RemoteInvocation implements Serializable {
 	 * @see #addAttribute
 	 * @see #getAttribute
 	 */
-	public void setAttributes(Map<String, Serializable> attributes) {
+	public void setAttributes(@Nullable Map<String, Serializable> attributes) {
 		this.attributes = attributes;
 	}
 

spring-context/src/main/java/org/springframework/remoting/support/RemoteInvocationResult.java

@@ -41,8 +41,10 @@ public class RemoteInvocationResult implements Serializable {
 	private static final long serialVersionUID = 2138555143707773549L;
 
 
+	@Nullable
 	private Object value;
 
+	@Nullable
 	private Throwable exception;
 
 
@@ -81,7 +83,7 @@ public class RemoteInvocationResult implements Serializable {
 	 * Use {@link #RemoteInvocationResult(Object)} otherwise.
 	 * @see #RemoteInvocationResult()
 	 */
-	public void setValue(Object value) {
+	public void setValue(@Nullable Object value) {
 		this.value = value;
 	}
 
@@ -102,7 +104,7 @@ public class RemoteInvocationResult implements Serializable {
 	 * Use {@link #RemoteInvocationResult(Throwable)} otherwise.
 	 * @see #RemoteInvocationResult()
 	 */
-	public void setException(Throwable exception) {
+	public void setException(@Nullable Throwable exception) {
 		this.exception = exception;
 	}
 

spring-context/src/main/java/org/springframework/scheduling/config/ScheduledTaskRegistrar.java

@@ -92,9 +92,11 @@ public class ScheduledTaskRegistrar implements InitializingBean, DisposableBean
 	 * {@link java.util.concurrent.ScheduledExecutorService} to be wrapped as a
 	 * {@code TaskScheduler}.
 	 */
-	public void setScheduler(Object scheduler) {
-		Assert.notNull(scheduler, "Scheduler object must not be null");
-		if (scheduler instanceof TaskScheduler) {
+	public void setScheduler(@Nullable Object scheduler) {
+		if (scheduler == null) {
+			this.taskScheduler = null;
+		}
+		else if (scheduler instanceof TaskScheduler) {
 			this.taskScheduler = (TaskScheduler) scheduler;
 		}
 		else if (scheduler instanceof ScheduledExecutorService) {

spring-context/src/main/java/org/springframework/validation/DataBinder.java

@@ -424,7 +424,7 @@ public class DataBinder implements PropertyEditorRegistry, TypeConverter {
 	 * @see #setDisallowedFields
 	 * @see #isAllowed(String)
 	 */
-	public void setAllowedFields(String... allowedFields) {
+	public void setAllowedFields(@Nullable String... allowedFields) {
 		this.allowedFields = PropertyAccessorUtils.canonicalPropertyNames(allowedFields);
 	}
 
@@ -448,7 +448,7 @@ public class DataBinder implements PropertyEditorRegistry, TypeConverter {
 	 * @see #setAllowedFields
 	 * @see #isAllowed(String)
 	 */
-	public void setDisallowedFields(String... disallowedFields) {
+	public void setDisallowedFields(@Nullable String... disallowedFields) {
 		this.disallowedFields = PropertyAccessorUtils.canonicalPropertyNames(disallowedFields);
 	}
 
@@ -471,7 +471,7 @@ public class DataBinder implements PropertyEditorRegistry, TypeConverter {
 	 * @see #setBindingErrorProcessor
 	 * @see DefaultBindingErrorProcessor#MISSING_FIELD_ERROR_CODE
 	 */
-	public void setRequiredFields(String... requiredFields) {
+	public void setRequiredFields(@Nullable String... requiredFields) {
 		this.requiredFields = PropertyAccessorUtils.canonicalPropertyNames(requiredFields);
 		if (logger.isDebugEnabled()) {
 			logger.debug("DataBinder requires binding of required fields [" +
@@ -526,14 +526,18 @@ public class DataBinder implements PropertyEditorRegistry, TypeConverter {
 	 * @see #addValidators(Validator...)
 	 * @see #replaceValidators(Validator...)
 	 */
-	public void setValidator(Validator validator) {
+	public void setValidator(@Nullable Validator validator) {
 		assertValidators(validator);
 		this.validators.clear();
-		this.validators.add(validator);
+		if (validator != null) {
+			this.validators.add(validator);
+		}
 	}
 
 	private void assertValidators(Validator... validators) {
-		Assert.notNull(validators, "Validators required");
+		if (validators == null) {
+			return;
+		}
 		for (Validator validator : validators) {
 			if (validator != null && (getTarget() != null && !validator.supports(getTarget().getClass()))) {
 				throw new IllegalStateException("Invalid target for Validator [" + validator + "]: " + getTarget());

spring-core/src/main/java/org/springframework/core/convert/support/ConvertingPropertyEditorAdapter.java

@@ -56,7 +56,7 @@ public class ConvertingPropertyEditorAdapter extends PropertyEditorSupport {
 
 
 	@Override
-	public void setAsText(String text) throws IllegalArgumentException {
+	public void setAsText(@Nullable String text) throws IllegalArgumentException {
 		setValue(this.conversionService.convert(text, TypeDescriptor.valueOf(String.class), this.targetDescriptor));
 	}
 

spring-core/src/main/java/org/springframework/core/task/SimpleAsyncTaskExecutor.java

@@ -103,7 +103,7 @@ public class SimpleAsyncTaskExecutor extends CustomizableThreadCreator implement
 	 * @see #setThreadNamePrefix
 	 * @see #setThreadPriority
 	 */
-	public void setThreadFactory(ThreadFactory threadFactory) {
+	public void setThreadFactory(@Nullable ThreadFactory threadFactory) {
 		this.threadFactory = threadFactory;
 	}
 

spring-core/src/main/java/org/springframework/util/CollectionUtils.java

@@ -430,7 +430,7 @@ public abstract class CollectionUtils {
 		}
 
 		@Override
-		public void set(K key, V value) {
+		public void set(K key, @Nullable V value) {
 			List<V> values = new LinkedList<>();
 			values.add(value);
 			this.map.put(key, values);

spring-core/src/main/java/org/springframework/util/CustomizableThreadCreator.java

@@ -127,7 +127,7 @@ public class CustomizableThreadCreator implements Serializable {
 	 * Specify the thread group that threads should be created in.
 	 * @see #setThreadGroupName
 	 */
-	public void setThreadGroup(ThreadGroup threadGroup) {
+	public void setThreadGroup(@Nullable ThreadGroup threadGroup) {
 		this.threadGroup = threadGroup;
 	}
 

spring-core/src/main/java/org/springframework/util/LinkedMultiValueMap.java

@@ -101,7 +101,7 @@ public class LinkedMultiValueMap<K, V> implements MultiValueMap<K, V>, Serializa
 	}
 
 	@Override
-	public void set(K key, V value) {
+	public void set(K key, @Nullable V value) {
 		List<V> values = new LinkedList<>();
 		values.add(value);
 		this.targetMap.put(key, values);

spring-core/src/main/java/org/springframework/util/MethodInvoker.java

@@ -65,7 +65,7 @@ public class MethodInvoker {
 	 * @see #setTargetObject
 	 * @see #setTargetMethod
 	 */
-	public void setTargetClass(Class<?> targetClass) {
+	public void setTargetClass(@Nullable Class<?> targetClass) {
 		this.targetClass = targetClass;
 	}
 
@@ -106,7 +106,7 @@ public class MethodInvoker {
 	 * @see #setTargetClass
 	 * @see #setTargetObject
 	 */
-	public void setTargetMethod(String targetMethod) {
+	public void setTargetMethod(@Nullable String targetMethod) {
 		this.targetMethod = targetMethod;
 	}
 

spring-core/src/main/java/org/springframework/util/MultiValueMap.java

@@ -64,7 +64,7 @@ public interface MultiValueMap<K, V> extends Map<K, List<V>> {
 	 * @param key the key
 	 * @param value the value to set
 	 */
-	void set(K key, V value);
+	void set(K key, @Nullable V value);
 
 	/**
 	 * Set the given values under.

spring-core/src/main/java/org/springframework/util/xml/AbstractXMLReader.java

@@ -41,19 +41,24 @@ import org.springframework.lang.Nullable;
  */
 abstract class AbstractXMLReader implements XMLReader {
 
+	@Nullable
 	private DTDHandler dtdHandler;
 
+	@Nullable
 	private ContentHandler contentHandler;
 
+	@Nullable
 	private EntityResolver entityResolver;
 
+	@Nullable
 	private ErrorHandler errorHandler;
 
+	@Nullable
 	private LexicalHandler lexicalHandler;
 
 
 	@Override
-	public void setContentHandler(ContentHandler contentHandler) {
+	public void setContentHandler(@Nullable ContentHandler contentHandler) {
 		this.contentHandler = contentHandler;
 	}
 
@@ -64,7 +69,7 @@ abstract class AbstractXMLReader implements XMLReader {
 	}
 
 	@Override
-	public void setDTDHandler(DTDHandler dtdHandler) {
+	public void setDTDHandler(@Nullable DTDHandler dtdHandler) {
 		this.dtdHandler = dtdHandler;
 	}
 
@@ -75,7 +80,7 @@ abstract class AbstractXMLReader implements XMLReader {
 	}
 
 	@Override
-	public void setEntityResolver(EntityResolver entityResolver) {
+	public void setEntityResolver(@Nullable EntityResolver entityResolver) {
 		this.entityResolver = entityResolver;
 	}
 
@@ -86,7 +91,7 @@ abstract class AbstractXMLReader implements XMLReader {
 	}
 
 	@Override
-	public void setErrorHandler(ErrorHandler errorHandler) {
+	public void setErrorHandler(@Nullable ErrorHandler errorHandler) {
 		this.errorHandler = errorHandler;
 	}
 

spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/CallMetaDataContext.java

@@ -143,7 +143,7 @@ public class CallMetaDataContext {
 	/**
 	 * Specify the name of the procedure.
 	 */
-	public void setProcedureName(String procedureName) {
+	public void setProcedureName(@Nullable String procedureName) {
 		this.procedureName = procedureName;
 	}
 
@@ -158,7 +158,7 @@ public class CallMetaDataContext {
 	/**
 	 * Specify the name of the catalog.
 	 */
-	public void setCatalogName(String catalogName) {
+	public void setCatalogName(@Nullable String catalogName) {
 		this.catalogName = catalogName;
 	}
 
@@ -173,7 +173,7 @@ public class CallMetaDataContext {
 	/**
 	 * Secify the name of the schema.
 	 */
-	public void setSchemaName(String schemaName) {
+	public void setSchemaName(@Nullable String schemaName) {
 		this.schemaName = schemaName;
 	}
 

spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/TableMetaDataContext.java

@@ -75,7 +75,7 @@ public class TableMetaDataContext {
 	/**
 	 * Set the name of the table for this context.
 	 */
-	public void setTableName(String tableName) {
+	public void setTableName(@Nullable String tableName) {
 		this.tableName = tableName;
 	}
 
@@ -90,7 +90,7 @@ public class TableMetaDataContext {
 	/**
 	 * Set the name of the catalog for this context.
 	 */
-	public void setCatalogName(String catalogName) {
+	public void setCatalogName(@Nullable String catalogName) {
 		this.catalogName = catalogName;
 	}
 
@@ -105,7 +105,7 @@ public class TableMetaDataContext {
 	/**
 	 * Set the name of the schema for this context.
 	 */
-	public void setSchemaName(String schemaName) {
+	public void setSchemaName(@Nullable String schemaName) {
 		this.schemaName = schemaName;
 	}
 

spring-jdbc/src/main/java/org/springframework/jdbc/core/simple/AbstractJdbcCall.java

@@ -108,7 +108,7 @@ public abstract class AbstractJdbcCall {
 	/**
 	 * Set the name of the stored procedure.
 	 */
-	public void setProcedureName(String procedureName) {
+	public void setProcedureName(@Nullable String procedureName) {
 		this.callMetaDataContext.setProcedureName(procedureName);
 	}
 
@@ -137,7 +137,7 @@ public abstract class AbstractJdbcCall {
 	/**
 	 * Set the catalog name to use.
 	 */
-	public void setCatalogName(String catalogName) {
+	public void setCatalogName(@Nullable String catalogName) {
 		this.callMetaDataContext.setCatalogName(catalogName);
 	}
 
@@ -152,7 +152,7 @@ public abstract class AbstractJdbcCall {
 	/**
 	 * Set the schema name to use.
 	 */
-	public void setSchemaName(String schemaName) {
+	public void setSchemaName(@Nullable String schemaName) {
 		this.callMetaDataContext.setSchemaName(schemaName);
 	}
 

spring-jdbc/src/main/java/org/springframework/jdbc/core/simple/AbstractJdbcInsert.java

@@ -119,7 +119,7 @@ public abstract class AbstractJdbcInsert {
 	/**
 	 * Set the name of the table for this insert.
 	 */
-	public void setTableName(String tableName) {
+	public void setTableName(@Nullable String tableName) {
 		checkIfConfigurationModificationIsAllowed();
 		this.tableMetaDataContext.setTableName(tableName);
 	}
@@ -135,7 +135,7 @@ public abstract class AbstractJdbcInsert {
 	/**
 	 * Set the name of the schema for this insert.
 	 */
-	public void setSchemaName(String schemaName) {
+	public void setSchemaName(@Nullable String schemaName) {
 		checkIfConfigurationModificationIsAllowed();
 		this.tableMetaDataContext.setSchemaName(schemaName);
 	}
@@ -151,7 +151,7 @@ public abstract class AbstractJdbcInsert {
 	/**
 	 * Set the name of the catalog for this insert.
 	 */
-	public void setCatalogName(String catalogName) {
+	public void setCatalogName(@Nullable String catalogName) {
 		checkIfConfigurationModificationIsAllowed();
 		this.tableMetaDataContext.setCatalogName(catalogName);
 	}

spring-jdbc/src/main/java/org/springframework/jdbc/core/support/JdbcDaoSupport.java

@@ -84,7 +84,7 @@ public abstract class JdbcDaoSupport extends DaoSupport {
 	 * Set the JdbcTemplate for this DAO explicitly,
 	 * as an alternative to specifying a DataSource.
 	 */
-	public final void setJdbcTemplate(JdbcTemplate jdbcTemplate) {
+	public final void setJdbcTemplate(@Nullable JdbcTemplate jdbcTemplate) {
 		this.jdbcTemplate = jdbcTemplate;
 		initTemplateConfig();
 	}

spring-jdbc/src/main/java/org/springframework/jdbc/datasource/AbstractDriverBasedDataSource.java

@@ -57,7 +57,7 @@ public abstract class AbstractDriverBasedDataSource extends AbstractDataSource {
 	 * Set the JDBC URL to use for connecting through the Driver.
 	 * @see java.sql.Driver#connect(String, java.util.Properties)
 	 */
-	public void setUrl(String url) {
+	public void setUrl(@Nullable String url) {
 		Assert.hasText(url, "Property 'url' must not be empty");
 		this.url = url.trim();
 	}
@@ -74,7 +74,7 @@ public abstract class AbstractDriverBasedDataSource extends AbstractDataSource {
 	 * Set the JDBC username to use for connecting through the Driver.
 	 * @see java.sql.Driver#connect(String, java.util.Properties)
 	 */
-	public void setUsername(String username) {
+	public void setUsername(@Nullable String username) {
 		this.username = username;
 	}
 
@@ -90,7 +90,7 @@ public abstract class AbstractDriverBasedDataSource extends AbstractDataSource {
 	 * Set the JDBC password to use for connecting through the Driver.
 	 * @see java.sql.Driver#connect(String, java.util.Properties)
 	 */
-	public void setPassword(String password) {
+	public void setPassword(@Nullable String password) {
 		this.password = password;
 	}
 
@@ -107,7 +107,7 @@ public abstract class AbstractDriverBasedDataSource extends AbstractDataSource {
 	 * @since 4.3.2
 	 * @see Connection#setCatalog
 	 */
-	public void setCatalog(String catalog) {
+	public void setCatalog(@Nullable String catalog) {
 		this.catalog = catalog;
 	}
 
@@ -125,7 +125,7 @@ public abstract class AbstractDriverBasedDataSource extends AbstractDataSource {
 	 * @since 4.3.2
 	 * @see Connection#setSchema
 	 */
-	public void setSchema(String schema) {
+	public void setSchema(@Nullable String schema) {
 		this.schema = schema;
 	}
 
@@ -146,7 +146,7 @@ public abstract class AbstractDriverBasedDataSource extends AbstractDataSource {
 	 * DataSource will override the corresponding connection properties.
 	 * @see java.sql.Driver#connect(String, java.util.Properties)
 	 */
-	public void setConnectionProperties(Properties connectionProperties) {
+	public void setConnectionProperties(@Nullable Properties connectionProperties) {
 		this.connectionProperties = connectionProperties;
 	}
 

spring-jdbc/src/main/java/org/springframework/jdbc/datasource/DataSourceTransactionManager.java

@@ -155,7 +155,7 @@ public class DataSourceTransactionManager extends AbstractPlatformTransactionMan
 	 * @see TransactionAwareDataSourceProxy
 	 * @see org.springframework.transaction.jta.JtaTransactionManager
 	 */
-	public void setDataSource(DataSource dataSource) {
+	public void setDataSource(@Nullable DataSource dataSource) {
 		if (dataSource instanceof TransactionAwareDataSourceProxy) {
 			// If we got a TransactionAwareDataSourceProxy, we need to perform transactions
 			// for its underlying target DataSource, else data access code won't see

spring-jdbc/src/main/java/org/springframework/jdbc/datasource/DelegatingDataSource.java

@@ -40,6 +40,7 @@ import org.springframework.util.Assert;
  */
 public class DelegatingDataSource implements DataSource, InitializingBean {
 
+	@Nullable
 	private DataSource targetDataSource;
 
 
@@ -62,8 +63,7 @@ public class DelegatingDataSource implements DataSource, InitializingBean {
 	/**
 	 * Set the target DataSource that this DataSource should delegate to.
 	 */
-	public void setTargetDataSource(DataSource targetDataSource) {
-		Assert.notNull(targetDataSource, "'targetDataSource' must not be null");
+	public void setTargetDataSource(@Nullable DataSource targetDataSource) {
 		this.targetDataSource = targetDataSource;
 	}
 

spring-jdbc/src/main/java/org/springframework/jdbc/support/AbstractFallbackSQLExceptionTranslator.java

@@ -38,6 +38,7 @@ public abstract class AbstractFallbackSQLExceptionTranslator implements SQLExcep
 	/** Logger available to subclasses */
 	protected final Log logger = LogFactory.getLog(getClass());
 
+	@Nullable
 	private SQLExceptionTranslator fallbackTranslator;
 
 
@@ -45,7 +46,7 @@ public abstract class AbstractFallbackSQLExceptionTranslator implements SQLExcep
 	 * Override the default SQL state fallback translator
 	 * (typically a {@link SQLStateSQLExceptionTranslator}).
 	 */
-	public void setFallbackTranslator(SQLExceptionTranslator fallback) {
+	public void setFallbackTranslator(@Nullable SQLExceptionTranslator fallback) {
 		this.fallbackTranslator = fallback;
 	}
 

spring-jdbc/src/main/java/org/springframework/jdbc/support/CustomSQLErrorCodesTranslation.java

@@ -53,8 +53,8 @@ public class CustomSQLErrorCodesTranslation {
 	/**
 	 * Set the exception class for the specified error codes.
 	 */
-	public void setExceptionClass(Class<?> exceptionClass) {
-		if (!DataAccessException.class.isAssignableFrom(exceptionClass)) {
+	public void setExceptionClass(@Nullable Class<?> exceptionClass) {
+		if (exceptionClass != null && !DataAccessException.class.isAssignableFrom(exceptionClass)) {
 			throw new IllegalArgumentException("Invalid exception class [" + exceptionClass +
 					"]: needs to be a subclass of [org.springframework.dao.DataAccessException]");
 		}

spring-jdbc/src/main/java/org/springframework/jdbc/support/JdbcAccessor.java

@@ -54,7 +54,7 @@ public abstract class JdbcAccessor implements InitializingBean {
 	/**
 	 * Set the JDBC DataSource to obtain connections from.
 	 */
-	public void setDataSource(DataSource dataSource) {
+	public void setDataSource(@Nullable DataSource dataSource) {
 		this.dataSource = dataSource;
 	}
 

spring-jdbc/src/main/java/org/springframework/jdbc/support/SQLErrorCodeSQLExceptionTranslator.java

@@ -152,7 +152,7 @@ public class SQLErrorCodeSQLExceptionTranslator extends AbstractFallbackSQLExcep
 	 * Set custom error codes to be used for translation.
 	 * @param sec custom error codes to use
 	 */
-	public void setSqlErrorCodes(SQLErrorCodes sec) {
+	public void setSqlErrorCodes(@Nullable SQLErrorCodes sec) {
 		this.sqlErrorCodes = sec;
 	}
 

spring-jdbc/src/main/java/org/springframework/jdbc/support/SQLErrorCodes.java

@@ -71,7 +71,7 @@ public class SQLErrorCodes {
 	 * Set this property if the database name contains spaces,
 	 * in which case we can not use the bean name for lookup.
 	 */
-	public void setDatabaseProductName(String databaseProductName) {
+	public void setDatabaseProductName(@Nullable String databaseProductName) {
 		this.databaseProductNames = new String[] {databaseProductName};
 	}
 
@@ -85,7 +85,7 @@ public class SQLErrorCodes {
 	 * Set this property to specify multiple database names that contains spaces,
 	 * in which case we can not use bean names for lookup.
 	 */
-	public void setDatabaseProductNames(String... databaseProductNames) {
+	public void setDatabaseProductNames(@Nullable String... databaseProductNames) {
 		this.databaseProductNames = databaseProductNames;
 	}
 
@@ -210,7 +210,7 @@ public class SQLErrorCodes {
 		}
 	}
 
-	public void setCustomSqlExceptionTranslator(SQLExceptionTranslator customSqlExceptionTranslator) {
+	public void setCustomSqlExceptionTranslator(@Nullable SQLExceptionTranslator customSqlExceptionTranslator) {
 		this.customSqlExceptionTranslator = customSqlExceptionTranslator;
 	}
 

spring-jms/src/main/java/org/springframework/jms/config/JmsListenerEndpointRegistrar.java

@@ -63,7 +63,7 @@ public class JmsListenerEndpointRegistrar implements BeanFactoryAware, Initializ
 	/**
 	 * Set the {@link JmsListenerEndpointRegistry} instance to use.
 	 */
-	public void setEndpointRegistry(JmsListenerEndpointRegistry endpointRegistry) {
+	public void setEndpointRegistry(@Nullable JmsListenerEndpointRegistry endpointRegistry) {
 		this.endpointRegistry = endpointRegistry;
 	}
 
@@ -84,7 +84,7 @@ public class JmsListenerEndpointRegistrar implements BeanFactoryAware, Initializ
 	 * or to customize conversion and validation support. See
 	 * {@link DefaultMessageHandlerMethodFactory} javadoc for more details.
 	 */
-	public void setMessageHandlerMethodFactory(MessageHandlerMethodFactory messageHandlerMethodFactory) {
+	public void setMessageHandlerMethodFactory(@Nullable MessageHandlerMethodFactory messageHandlerMethodFactory) {
 		this.messageHandlerMethodFactory = messageHandlerMethodFactory;
 	}
 

spring-jms/src/main/java/org/springframework/jms/config/MethodJmsListenerEndpoint.java

@@ -68,7 +68,7 @@ public class MethodJmsListenerEndpoint extends AbstractJmsListenerEndpoint imple
 	/**
 	 * Set the actual bean instance to invoke this endpoint method on.
 	 */
-	public void setBean(Object bean) {
+	public void setBean(@Nullable Object bean) {
 		this.bean = bean;
 	}
 
@@ -80,7 +80,7 @@ public class MethodJmsListenerEndpoint extends AbstractJmsListenerEndpoint imple
 	/**
 	 * Set the method to invoke for processing a message managed by this endpoint.
 	 */
-	public void setMethod(Method method) {
+	public void setMethod(@Nullable Method method) {
 		this.method = method;
 	}
 
@@ -95,7 +95,7 @@ public class MethodJmsListenerEndpoint extends AbstractJmsListenerEndpoint imple
 	 * (if annotated itself, that is, if not just annotated in an interface).
 	 * @since 4.2.3
 	 */
-	public void setMostSpecificMethod(Method mostSpecificMethod) {
+	public void setMostSpecificMethod(@Nullable Method mostSpecificMethod) {
 		this.mostSpecificMethod = mostSpecificMethod;
 	}
 

spring-jms/src/main/java/org/springframework/jms/config/SimpleJmsListenerEndpoint.java

@@ -39,7 +39,7 @@ public class SimpleJmsListenerEndpoint extends AbstractJmsListenerEndpoint {
 	 * Set the {@link MessageListener} to invoke when a message matching
 	 * the endpoint is received.
 	 */
-	public void setMessageListener(MessageListener messageListener) {
+	public void setMessageListener(@Nullable MessageListener messageListener) {
 		this.messageListener = messageListener;
 	}
 

spring-jms/src/main/java/org/springframework/jms/connection/DelegatingConnectionFactory.java

@@ -55,6 +55,7 @@ import org.springframework.util.Assert;
 public class DelegatingConnectionFactory
 		implements SmartConnectionFactory, QueueConnectionFactory, TopicConnectionFactory, InitializingBean {
 
+	@Nullable
 	private ConnectionFactory targetConnectionFactory;
 
 	private boolean shouldStopConnections = false;
@@ -63,8 +64,7 @@ public class DelegatingConnectionFactory
 	/**
 	 * Set the target ConnectionFactory that this ConnectionFactory should delegate to.
 	 */
-	public void setTargetConnectionFactory(ConnectionFactory targetConnectionFactory) {
-		Assert.notNull(targetConnectionFactory, "'targetConnectionFactory' must not be null");
+	public void setTargetConnectionFactory(@Nullable ConnectionFactory targetConnectionFactory) {
 		this.targetConnectionFactory = targetConnectionFactory;
 	}
 

spring-jms/src/main/java/org/springframework/jms/connection/JmsTransactionManager.java

@@ -127,8 +127,8 @@ public class JmsTransactionManager extends AbstractPlatformTransactionManager
 	/**
 	 * Set the JMS ConnectionFactory that this instance should manage transactions for.
 	 */
-	public void setConnectionFactory(ConnectionFactory cf) {
-		if (cf instanceof TransactionAwareConnectionFactoryProxy) {
+	public void setConnectionFactory(@Nullable ConnectionFactory cf) {
+		if (cf != null && cf instanceof TransactionAwareConnectionFactoryProxy) {
 			// If we got a TransactionAwareConnectionFactoryProxy, we need to perform transactions
 			// for its underlying target ConnectionFactory, else JMS access code won't see
 			// properly exposed transactions (i.e. transactions for the target ConnectionFactory).

spring-jms/src/main/java/org/springframework/jms/connection/SingleConnectionFactory.java

@@ -143,7 +143,7 @@ public class SingleConnectionFactory implements ConnectionFactory, QueueConnecti
 	 * Set the target ConnectionFactory which will be used to lazily
 	 * create a single Connection.
 	 */
-	public void setTargetConnectionFactory(ConnectionFactory targetConnectionFactory) {
+	public void setTargetConnectionFactory(@Nullable ConnectionFactory targetConnectionFactory) {
 		this.targetConnectionFactory = targetConnectionFactory;
 	}
 
@@ -151,7 +151,7 @@ public class SingleConnectionFactory implements ConnectionFactory, QueueConnecti
 	 * Return the target ConnectionFactory which will be used to lazily
 	 * create a single Connection, if any.
 	 */
-	@org.springframework.lang.Nullable
+	@Nullable
 	public ConnectionFactory getTargetConnectionFactory() {
 		return this.targetConnectionFactory;
 	}
@@ -165,7 +165,7 @@ public class SingleConnectionFactory implements ConnectionFactory, QueueConnecti
 	 * @see javax.jms.Connection#setClientID
 	 * @see #setTargetConnectionFactory
 	 */
-	public void setClientId(String clientId) {
+	public void setClientId(@Nullable String clientId) {
 		this.clientId = clientId;
 	}
 
@@ -173,7 +173,7 @@ public class SingleConnectionFactory implements ConnectionFactory, QueueConnecti
 	 * Return a JMS client ID for the single Connection created and exposed
 	 * by this ConnectionFactory, if any.
 	 */
-	@org.springframework.lang.Nullable
+	@Nullable
 	protected String getClientId() {
 		return this.clientId;
 	}
@@ -183,7 +183,7 @@ public class SingleConnectionFactory implements ConnectionFactory, QueueConnecti
 	 * registered with the single Connection created by this factory.
 	 * @see #setReconnectOnException
 	 */
-	public void setExceptionListener(ExceptionListener exceptionListener) {
+	public void setExceptionListener(@Nullable ExceptionListener exceptionListener) {
 		this.exceptionListener = exceptionListener;
 	}
 

spring-jms/src/main/java/org/springframework/jms/connection/TransactionAwareConnectionFactoryProxy.java

@@ -81,6 +81,7 @@ public class TransactionAwareConnectionFactoryProxy
 
 	private boolean synchedLocalTransactionAllowed = false;
 
+	@Nullable
 	private ConnectionFactory targetConnectionFactory;
 
 
@@ -102,8 +103,7 @@ public class TransactionAwareConnectionFactoryProxy
 	/**
 	 * Set the target ConnectionFactory that this ConnectionFactory should delegate to.
 	 */
-	public final void setTargetConnectionFactory(ConnectionFactory targetConnectionFactory) {
-		Assert.notNull(targetConnectionFactory, "'targetConnectionFactory' must not be null");
+	public final void setTargetConnectionFactory(@Nullable ConnectionFactory targetConnectionFactory) {
 		this.targetConnectionFactory = targetConnectionFactory;
 	}
 

spring-jms/src/main/java/org/springframework/jms/core/JmsMessagingTemplate.java

@@ -106,7 +106,7 @@ public class JmsMessagingTemplate extends AbstractMessagingTemplate<Destination>
 	/**
 	 * Set the {@link JmsTemplate} to use.
 	 */
-	public void setJmsTemplate(JmsTemplate jmsTemplate) {
+	public void setJmsTemplate(@Nullable JmsTemplate jmsTemplate) {
 		this.jmsTemplate = jmsTemplate;
 	}
 
@@ -147,7 +147,7 @@ public class JmsMessagingTemplate extends AbstractMessagingTemplate<Destination>
 	 * without a destination argument will raise an exception if invoked.
 	 * @see #setDefaultDestination(Object)
 	 */
-	public void setDefaultDestinationName(String defaultDestinationName) {
+	public void setDefaultDestinationName(@Nullable String defaultDestinationName) {
 		this.defaultDestinationName = defaultDestinationName;
 	}
 

spring-jms/src/main/java/org/springframework/jms/core/JmsTemplate.java

@@ -92,6 +92,7 @@ public class JmsTemplate extends JmsDestinationAccessor implements JmsOperations
 	private final JmsTemplateResourceFactory transactionalResourceFactory = new JmsTemplateResourceFactory();
 
 
+	@Nullable
 	private Object defaultDestination;
 
 	private MessageConverter messageConverter;
@@ -161,7 +162,7 @@ public class JmsTemplate extends JmsDestinationAccessor implements JmsOperations
 	 * @see #convertAndSend(Object, MessagePostProcessor)
 	 * @see #setDefaultDestinationName(String)
 	 */
-	public void setDefaultDestination(Destination destination) {
+	public void setDefaultDestination(@Nullable Destination destination) {
 		this.defaultDestination = destination;
 	}
 
@@ -195,7 +196,7 @@ public class JmsTemplate extends JmsDestinationAccessor implements JmsOperations
 	 * @see #setDestinationResolver
 	 * @see #setDefaultDestination(javax.jms.Destination)
 	 */
-	public void setDefaultDestinationName(String destinationName) {
+	public void setDefaultDestinationName(@Nullable String destinationName) {
 		this.defaultDestination = destinationName;
 	}
 
@@ -234,7 +235,6 @@ public class JmsTemplate extends JmsDestinationAccessor implements JmsOperations
 	/**
 	 * Return the message converter for this template.
 	 */
-	@Nullable
 	public MessageConverter getMessageConverter() {
 		return this.messageConverter;
 	}

spring-jms/src/main/java/org/springframework/jms/core/support/JmsGatewaySupport.java

@@ -84,7 +84,7 @@ public abstract class JmsGatewaySupport implements InitializingBean {
 	 * Set the JmsTemplate for the gateway.
 	 * @see #setConnectionFactory(javax.jms.ConnectionFactory)
 	 */
-	public final void setJmsTemplate(JmsTemplate jmsTemplate) {
+	public final void setJmsTemplate(@Nullable JmsTemplate jmsTemplate) {
 		this.jmsTemplate = jmsTemplate;
 	}
 

spring-jms/src/main/java/org/springframework/jms/listener/AbstractJmsListeningContainer.java

@@ -96,7 +96,7 @@ public abstract class AbstractJmsListeningContainer extends JmsDestinationAccess
 	 * @see javax.jms.Connection#setClientID
 	 * @see #setConnectionFactory
 	 */
-	public void setClientId(String clientId) {
+	public void setClientId(@Nullable String clientId) {
 		this.clientId = clientId;
 	}
 
@@ -143,7 +143,7 @@ public abstract class AbstractJmsListeningContainer extends JmsDestinationAccess
 	}
 
 	@Override
-	public void setBeanName(String beanName) {
+	public void setBeanName(@Nullable String beanName) {
 		this.beanName = beanName;
 	}
 

spring-jms/src/main/java/org/springframework/jms/listener/AbstractMessageListenerContainer.java

@@ -196,8 +196,7 @@ public abstract class AbstractMessageListenerContainer extends AbstractJmsListen
 	 * CACHE_CONSUMER). However, this is considered advanced usage; use it with care!
 	 * @see #setDestinationName(String)
 	 */
-	public void setDestination(Destination destination) {
-		Assert.notNull(destination, "'destination' must not be null");
+	public void setDestination(@Nullable Destination destination) {
 		this.destination = destination;
 		if (destination instanceof Topic && !(destination instanceof Queue)) {
 			// Clearly a Topic: let's set the "pubSubDomain" flag accordingly.
@@ -226,8 +225,7 @@ public abstract class AbstractMessageListenerContainer extends AbstractJmsListen
 	 * CACHE_CONSUMER). However, this is considered advanced usage; use it with care!
 	 * @see #setDestination(javax.jms.Destination)
 	 */
-	public void setDestinationName(String destinationName) {
-		Assert.notNull(destinationName, "'destinationName' must not be null");
+	public void setDestinationName(@Nullable String destinationName) {
 		this.destination = destinationName;
 	}
 
@@ -286,10 +284,10 @@ public abstract class AbstractMessageListenerContainer extends AbstractJmsListen
 	 * @see javax.jms.MessageListener
 	 * @see SessionAwareMessageListener
 	 */
-	public void setMessageListener(Object messageListener) {
+	public void setMessageListener(@Nullable Object messageListener) {
 		checkMessageListener(messageListener);
 		this.messageListener = messageListener;
-		if (this.subscriptionName == null) {
+		if (messageListener != null && this.subscriptionName == null) {
 			this.subscriptionName = getDefaultSubscriptionName(messageListener);
 		}
 	}
@@ -313,8 +311,8 @@ public abstract class AbstractMessageListenerContainer extends AbstractJmsListen
 	 * @see javax.jms.MessageListener
 	 * @see SessionAwareMessageListener
 	 */
-	protected void checkMessageListener(Object messageListener) {
-		if (!(messageListener instanceof MessageListener ||
+	protected void checkMessageListener(@Nullable Object messageListener) {
+		if (messageListener != null && !(messageListener instanceof MessageListener ||
 				messageListener instanceof SessionAwareMessageListener)) {
 			throw new IllegalArgumentException(
 					"Message listener needs to be of type [" + MessageListener.class.getName() +
@@ -408,7 +406,7 @@ public abstract class AbstractMessageListenerContainer extends AbstractJmsListen
 	 * @see #setClientId
 	 * @see #setMessageListener
 	 */
-	public void setSubscriptionName(String subscriptionName) {
+	public void setSubscriptionName(@Nullable String subscriptionName) {
 		this.subscriptionName = subscriptionName;
 	}
 
@@ -435,9 +433,9 @@ public abstract class AbstractMessageListenerContainer extends AbstractJmsListen
 	 * @see #setClientId
 	 * @see #setMessageListener
 	 */
-	public void setDurableSubscriptionName(String durableSubscriptionName) {
+	public void setDurableSubscriptionName(@Nullable String durableSubscriptionName) {
 		this.subscriptionName = durableSubscriptionName;
-		this.subscriptionDurable = true;
+		this.subscriptionDurable = (durableSubscriptionName != null);
 	}
 
 	/**
@@ -529,7 +527,7 @@ public abstract class AbstractMessageListenerContainer extends AbstractJmsListen
 	 * Set the JMS ExceptionListener to notify in case of a JMSException thrown
 	 * by the registered message listener or the invocation infrastructure.
 	 */
-	public void setExceptionListener(ExceptionListener exceptionListener) {
+	public void setExceptionListener(@Nullable ExceptionListener exceptionListener) {
 		this.exceptionListener = exceptionListener;
 	}
 
@@ -548,7 +546,7 @@ public abstract class AbstractMessageListenerContainer extends AbstractJmsListen
 	 * <p>By default, there will be <b>no</b> ErrorHandler so that error-level
 	 * logging is the only result.
 	 */
-	public void setErrorHandler(ErrorHandler errorHandler) {
+	public void setErrorHandler(@Nullable ErrorHandler errorHandler) {
 		this.errorHandler = errorHandler;
 	}
 

spring-jms/src/main/java/org/springframework/jms/listener/AbstractPollingMessageListenerContainer.java

@@ -123,7 +123,7 @@ public abstract class AbstractPollingMessageListenerContainer extends AbstractMe
 	 * @see org.springframework.transaction.jta.JtaTransactionManager
 	 * @see org.springframework.jms.connection.JmsTransactionManager
 	 */
-	public void setTransactionManager(PlatformTransactionManager transactionManager) {
+	public void setTransactionManager(@Nullable PlatformTransactionManager transactionManager) {
 		this.transactionManager = transactionManager;
 	}
 

spring-jms/src/main/java/org/springframework/jms/listener/adapter/AbstractAdaptableMessageListener.java

@@ -142,7 +142,7 @@ public abstract class AbstractAdaptableMessageListener
 	 * {@link javax.jms.TextMessage TextMessages} and
 	 * {@link javax.jms.ObjectMessage ObjectMessages}.
 	 */
-	public void setMessageConverter(MessageConverter messageConverter) {
+	public void setMessageConverter(@Nullable MessageConverter messageConverter) {
 		this.messageConverter = messageConverter;
 	}
 

spring-jms/src/main/java/org/springframework/jms/listener/endpoint/JmsActivationSpecConfig.java

@@ -78,7 +78,7 @@ public class JmsActivationSpecConfig {
 	private MessageConverter messageConverter;
 
 
-	public void setDestinationName(String destinationName) {
+	public void setDestinationName(@Nullable String destinationName) {
 		this.destinationName = destinationName;
 	}
 
@@ -108,7 +108,7 @@ public class JmsActivationSpecConfig {
 		}
 	}
 
-	public void setReplyQosSettings(QosSettings replyQosSettings) {
+	public void setReplyQosSettings(@Nullable QosSettings replyQosSettings) {
 		this.replyQosSettings = replyQosSettings;
 	}
 
@@ -139,7 +139,7 @@ public class JmsActivationSpecConfig {
 		return this.subscriptionShared;
 	}
 
-	public void setSubscriptionName(String subscriptionName) {
+	public void setSubscriptionName(@Nullable String subscriptionName) {
 		this.subscriptionName = subscriptionName;
 	}
 
@@ -148,9 +148,9 @@ public class JmsActivationSpecConfig {
 		return this.subscriptionName;
 	}
 
-	public void setDurableSubscriptionName(String durableSubscriptionName) {
+	public void setDurableSubscriptionName(@Nullable String durableSubscriptionName) {
 		this.subscriptionName = durableSubscriptionName;
-		this.subscriptionDurable = true;
+		this.subscriptionDurable = (durableSubscriptionName != null);
 	}
 
 	@Nullable
@@ -158,7 +158,7 @@ public class JmsActivationSpecConfig {
 		return (this.subscriptionDurable ? this.subscriptionName : null);
 	}
 
-	public void setClientId(String clientId) {
+	public void setClientId(@Nullable String clientId) {
 		this.clientId = clientId;
 	}
 
@@ -167,7 +167,7 @@ public class JmsActivationSpecConfig {
 		return this.clientId;
 	}
 
-	public void setMessageSelector(String messageSelector) {
+	public void setMessageSelector(@Nullable String messageSelector) {
 		this.messageSelector = messageSelector;
 	}
 
@@ -274,7 +274,7 @@ public class JmsActivationSpecConfig {
 	 * Set the {@link MessageConverter} strategy for converting JMS Messages.
 	 * @param messageConverter the message converter to use
 	 */
-	public void setMessageConverter(MessageConverter messageConverter) {
+	public void setMessageConverter(@Nullable MessageConverter messageConverter) {
 		this.messageConverter = messageConverter;
 	}
 

spring-jms/src/main/java/org/springframework/jms/listener/endpoint/JmsMessageEndpointManager.java

@@ -138,7 +138,7 @@ public class JmsMessageEndpointManager extends GenericMessageEndpointManager
 	 * <p>This config object will be turned into a concrete JCA 1.5 ActivationSpec
 	 * object through a {@link #setActivationSpecFactory JmsActivationSpecFactory}.
 	 */
-	public void setActivationSpecConfig(JmsActivationSpecConfig activationSpecConfig) {
+	public void setActivationSpecConfig(@Nullable JmsActivationSpecConfig activationSpecConfig) {
 		this.activationSpecConfig = activationSpecConfig;
 	}
 

spring-jms/src/main/java/org/springframework/jms/listener/endpoint/StandardJmsActivationSpecFactory.java

@@ -90,7 +90,7 @@ public class StandardJmsActivationSpecFactory implements JmsActivationSpecFactor
 	 * or {@link org.springframework.jms.support.destination.BeanFactoryDestinationResolver}
 	 * but not {@link org.springframework.jms.support.destination.DynamicDestinationResolver}.
 	 */
-	public void setDestinationResolver(DestinationResolver destinationResolver) {
+	public void setDestinationResolver(@Nullable DestinationResolver destinationResolver) {
 		this.destinationResolver = destinationResolver;
 	}
 

spring-jms/src/main/java/org/springframework/jms/remoting/JmsInvokerClientInterceptor.java

@@ -92,7 +92,7 @@ public class JmsInvokerClientInterceptor implements MethodInterceptor, Initializ
 	/**
 	 * Set the QueueConnectionFactory to use for obtaining JMS QueueConnections.
 	 */
-	public void setConnectionFactory(ConnectionFactory connectionFactory) {
+	public void setConnectionFactory(@Nullable ConnectionFactory connectionFactory) {
 		this.connectionFactory = connectionFactory;
 	}
 

spring-jms/src/main/java/org/springframework/jms/support/JmsAccessor.java

@@ -54,6 +54,7 @@ public abstract class JmsAccessor implements InitializingBean {
 	/** Logger available to subclasses */
 	protected final Log logger = LogFactory.getLog(getClass());
 
+	@Nullable
 	private ConnectionFactory connectionFactory;
 
 	private boolean sessionTransacted = false;
@@ -64,7 +65,7 @@ public abstract class JmsAccessor implements InitializingBean {
 	/**
 	 * Set the ConnectionFactory to use for obtaining JMS {@link Connection Connections}.
 	 */
-	public void setConnectionFactory(ConnectionFactory connectionFactory) {
+	public void setConnectionFactory(@Nullable ConnectionFactory connectionFactory) {
 		this.connectionFactory = connectionFactory;
 	}
 

spring-jms/src/test/java/org/springframework/jms/listener/AbstractMessageListenerContainerTests.java

@@ -16,6 +16,7 @@
 
 package org.springframework.jms.listener;
 
+import org.junit.Assert;
 import org.junit.Test;
 
 /**
@@ -28,10 +29,10 @@ public abstract class AbstractMessageListenerContainerTests {
 
 	protected abstract AbstractMessageListenerContainer getContainer();
 
-
-	@Test(expected = IllegalArgumentException.class)
-	public void testSettingMessageListenerToANullType() throws Exception {
+	
+	public void testSettingMessageListenerToANullType() {
 		getContainer().setMessageListener(null);
+		Assert.assertNull(getContainer().getMessageListener());
 	}
 
 	@Test(expected = IllegalArgumentException.class)

spring-messaging/src/main/java/org/springframework/messaging/converter/MarshallingMessageConverter.java

@@ -92,7 +92,7 @@ public class MarshallingMessageConverter extends AbstractMessageConverter {
 	/**
 	 * Set the {@link Marshaller} to be used by this message converter.
 	 */
-	public void setMarshaller(Marshaller marshaller) {
+	public void setMarshaller(@Nullable Marshaller marshaller) {
 		this.marshaller = marshaller;
 	}
 
@@ -107,7 +107,7 @@ public class MarshallingMessageConverter extends AbstractMessageConverter {
 	/**
 	 * Set the {@link Unmarshaller} to be used by this message converter.
 	 */
-	public void setUnmarshaller(Unmarshaller unmarshaller) {
+	public void setUnmarshaller(@Nullable Unmarshaller unmarshaller) {
 		this.unmarshaller = unmarshaller;
 	}
 

spring-messaging/src/main/java/org/springframework/messaging/core/AbstractDestinationResolvingMessagingTemplate.java

@@ -51,8 +51,7 @@ public abstract class AbstractDestinationResolvingMessagingTemplate<D> extends A
 	 * require resolving a destination name will raise an {@link IllegalArgumentException}.
 	 * @param destinationResolver the destination resolver to use
 	 */
-	public void setDestinationResolver(DestinationResolver<D> destinationResolver) {
-		Assert.notNull(destinationResolver, "'destinationResolver' is required");
+	public void setDestinationResolver(@Nullable DestinationResolver<D> destinationResolver) {
 		this.destinationResolver = destinationResolver;
 	}
 

spring-messaging/src/main/java/org/springframework/messaging/core/AbstractMessageSendingTemplate.java

@@ -63,7 +63,7 @@ public abstract class AbstractMessageSendingTemplate<D> implements MessageSendin
 	 * a destination argument. If a default destination is not configured, send methods
 	 * without a destination argument will raise an exception if invoked.
 	 */
-	public void setDefaultDestination(D defaultDestination) {
+	public void setDefaultDestination(@Nullable D defaultDestination) {
 		this.defaultDestination = defaultDestination;
 	}
 

spring-messaging/src/main/java/org/springframework/messaging/handler/invocation/AbstractMethodMessageHandler.java

@@ -96,6 +96,7 @@ public abstract class AbstractMethodMessageHandler<T>
 	private final HandlerMethodReturnValueHandlerComposite returnValueHandlers =
 			new HandlerMethodReturnValueHandlerComposite();
 
+	@Nullable
 	private ApplicationContext applicationContext;
 
 	private final Map<T, HandlerMethod> handlerMethods = new LinkedHashMap<>(64);
@@ -211,7 +212,7 @@ public abstract class AbstractMethodMessageHandler<T>
 	}
 
 	@Override
-	public void setApplicationContext(ApplicationContext applicationContext) {
+	public void setApplicationContext(@Nullable ApplicationContext applicationContext) {
 		this.applicationContext = applicationContext;
 	}
 

spring-messaging/src/main/java/org/springframework/messaging/simp/SimpMessageHeaderAccessor.java

@@ -121,8 +121,7 @@ public class SimpMessageHeaderAccessor extends NativeMessageHeaderAccessor {
 		return (SimpMessageType) getHeader(MESSAGE_TYPE_HEADER);
 	}
 
-	public void setDestination(String destination) {
-		Assert.notNull(destination, "Destination must not be null");
+	public void setDestination(@Nullable String destination) {
 		setHeader(DESTINATION_HEADER, destination);
 	}
 
@@ -155,7 +154,7 @@ public class SimpMessageHeaderAccessor extends NativeMessageHeaderAccessor {
 	/**
 	 * A static alternative for access to the session attributes header.
 	 */
-	public void setSessionAttributes(Map<String, Object> attributes) {
+	public void setSessionAttributes(@Nullable Map<String, Object> attributes) {
 		setHeader(SESSION_ATTRIBUTES, attributes);
 	}
 
@@ -168,7 +167,7 @@ public class SimpMessageHeaderAccessor extends NativeMessageHeaderAccessor {
 		return (Map<String, Object>) getHeader(SESSION_ATTRIBUTES);
 	}
 
-	public void setUser(Principal principal) {
+	public void setUser(@Nullable Principal principal) {
 		setHeader(USER_HEADER, principal);
 	}
 

spring-messaging/src/main/java/org/springframework/messaging/simp/SimpMessagingTemplate.java

@@ -111,7 +111,7 @@ public class SimpMessagingTemplate extends AbstractMessageSendingTemplate<String
 	 * messages created through the {@code SimpMessagingTemplate}.
 	 * <p>By default, this property is not set.
 	 */
-	public void setHeaderInitializer(MessageHeaderInitializer headerInitializer) {
+	public void setHeaderInitializer(@Nullable MessageHeaderInitializer headerInitializer) {
 		this.headerInitializer = headerInitializer;
 	}
 

spring-messaging/src/main/java/org/springframework/messaging/simp/annotation/support/SendToMethodReturnValueHandler.java

@@ -121,7 +121,7 @@ public class SendToMethodReturnValueHandler implements HandlerMethodReturnValueH
 	 * messages sent to the client outbound channel.
 	 * <p>By default this property is not set.
 	 */
-	public void setHeaderInitializer(MessageHeaderInitializer headerInitializer) {
+	public void setHeaderInitializer(@Nullable MessageHeaderInitializer headerInitializer) {
 		this.headerInitializer = headerInitializer;
 	}
 

spring-messaging/src/main/java/org/springframework/messaging/simp/annotation/support/SimpAnnotationMethodMessageHandler.java

@@ -234,7 +234,7 @@ public class SimpAnnotationMethodMessageHandler extends AbstractMethodMessageHan
 	 * @see org.springframework.validation.annotation.Validated
 	 * @see PayloadArgumentResolver
 	 */
-	public void setValidator(Validator validator) {
+	public void setValidator(@Nullable Validator validator) {
 		this.validator = validator;
 	}
 
@@ -249,7 +249,7 @@ public class SimpAnnotationMethodMessageHandler extends AbstractMethodMessageHan
 	 * that send messages from controller return values.
 	 * <p>By default, this property is not set.
 	 */
-	public void setHeaderInitializer(MessageHeaderInitializer headerInitializer) {
+	public void setHeaderInitializer(@Nullable MessageHeaderInitializer headerInitializer) {
 		this.headerInitializer = headerInitializer;
 	}
 

spring-messaging/src/main/java/org/springframework/messaging/simp/annotation/support/SubscriptionMethodReturnValueHandler.java

@@ -63,6 +63,7 @@ public class SubscriptionMethodReturnValueHandler implements HandlerMethodReturn
 
 	private final MessageSendingOperations<String> messagingTemplate;
 
+	@Nullable
 	private MessageHeaderInitializer headerInitializer;
 
 
@@ -82,7 +83,7 @@ public class SubscriptionMethodReturnValueHandler implements HandlerMethodReturn
 	 * messages sent to the client outbound channel.
 	 * <p>By default this property is not set.
 	 */
-	public void setHeaderInitializer(MessageHeaderInitializer headerInitializer) {
+	public void setHeaderInitializer(@Nullable MessageHeaderInitializer headerInitializer) {
 		this.headerInitializer = headerInitializer;
 	}
 

spring-messaging/src/main/java/org/springframework/messaging/simp/broker/AbstractBrokerMessageHandler.java

@@ -129,7 +129,7 @@ public abstract class AbstractBrokerMessageHandler
 	}
 
 	@Override
-	public void setApplicationEventPublisher(ApplicationEventPublisher publisher) {
+	public void setApplicationEventPublisher(@Nullable ApplicationEventPublisher publisher) {
 		this.eventPublisher = publisher;
 	}
 

spring-messaging/src/main/java/org/springframework/messaging/simp/broker/SimpleBrokerMessageHandler.java

@@ -157,10 +157,9 @@ public class SimpleBrokerMessageHandler extends AbstractBrokerMessageHandler {
 	 * <p>By default this is not set.
 	 * @since 4.2
 	 */
-	public void setTaskScheduler(TaskScheduler taskScheduler) {
-		Assert.notNull(taskScheduler, "TaskScheduler must not be null");
+	public void setTaskScheduler(@Nullable TaskScheduler taskScheduler) {
 		this.taskScheduler = taskScheduler;
-		if (this.heartbeatValue == null) {
+		if (taskScheduler != null && this.heartbeatValue == null) {
 			this.heartbeatValue = new long[] {10000, 10000};
 		}
 	}
@@ -183,8 +182,8 @@ public class SimpleBrokerMessageHandler extends AbstractBrokerMessageHandler {
 	 * (in milliseconds).
 	 * @since 4.2
 	 */
-	public void setHeartbeatValue(long[] heartbeat) {
-		if (heartbeat.length != 2 || heartbeat[0] < 0 || heartbeat[1] < 0) {
+	public void setHeartbeatValue(@Nullable long[] heartbeat) {
+		if (heartbeat != null && (heartbeat.length != 2 || heartbeat[0] < 0 || heartbeat[1] < 0)) {
 			throw new IllegalArgumentException("Invalid heart-beat: " + Arrays.toString(heartbeat));
 		}
 		this.heartbeatValue = heartbeat;
@@ -205,7 +204,7 @@ public class SimpleBrokerMessageHandler extends AbstractBrokerMessageHandler {
 	 * <p>By default this property is not set.
 	 * @since 4.1
 	 */
-	public void setHeaderInitializer(MessageHeaderInitializer headerInitializer) {
+	public void setHeaderInitializer(@Nullable MessageHeaderInitializer headerInitializer) {
 		this.headerInitializer = headerInitializer;
 	}
 

spring-messaging/src/main/java/org/springframework/messaging/simp/config/AbstractMessageBrokerConfiguration.java

@@ -112,7 +112,7 @@ public abstract class AbstractMessageBrokerConfiguration implements ApplicationC
 
 
 	@Override
-	public void setApplicationContext(ApplicationContext applicationContext) {
+	public void setApplicationContext(@Nullable ApplicationContext applicationContext) {
 		this.applicationContext = applicationContext;
 	}
 

spring-messaging/src/main/java/org/springframework/messaging/simp/stomp/StompBrokerRelayMessageHandler.java

@@ -325,7 +325,7 @@ public class StompBrokerRelayMessageHandler extends AbstractBrokerMessageHandler
 	 * providing the cloud-based STOMP service.
 	 * <p>By default this property is not set.
 	 */
-	public void setVirtualHost(String virtualHost) {
+	public void setVirtualHost(@Nullable String virtualHost) {
 		this.virtualHost = virtualHost;
 	}
 
@@ -341,7 +341,7 @@ public class StompBrokerRelayMessageHandler extends AbstractBrokerMessageHandler
 	 * Configure a TCP client for managing TCP connections to the STOMP broker.
 	 * <p>By default {@link ReactorNettyTcpClient} is used.
 	 */
-	public void setTcpClient(TcpOperations<byte[]> tcpClient) {
+	public void setTcpClient(@Nullable TcpOperations<byte[]> tcpClient) {
 		this.tcpClient = tcpClient;
 	}
 
@@ -361,7 +361,7 @@ public class StompBrokerRelayMessageHandler extends AbstractBrokerMessageHandler
 	 * are sent to the client outbound message channel.
 	 * <p>By default this property is not set.
 	 */
-	public void setHeaderInitializer(MessageHeaderInitializer headerInitializer) {
+	public void setHeaderInitializer(@Nullable MessageHeaderInitializer headerInitializer) {
 		this.headerInitializer = headerInitializer;
 	}
 

spring-messaging/src/main/java/org/springframework/messaging/simp/stomp/StompClientSupport.java

@@ -43,6 +43,7 @@ public abstract class StompClientSupport {
 
 	private MessageConverter messageConverter = new SimpleMessageConverter();
 
+	@Nullable
 	private TaskScheduler taskScheduler;
 
 	private long[] defaultHeartbeat = new long[] {10000, 10000};
@@ -76,7 +77,7 @@ public abstract class StompClientSupport {
 	 * Receipts however, if needed, do require a TaskScheduler to be configured.
 	 * <p>By default, this is not set.
 	 */
-	public void setTaskScheduler(TaskScheduler taskScheduler) {
+	public void setTaskScheduler(@Nullable TaskScheduler taskScheduler) {
 		this.taskScheduler = taskScheduler;
 	}
 

spring-messaging/src/main/java/org/springframework/messaging/simp/stomp/StompDecoder.java

@@ -61,7 +61,7 @@ public class StompDecoder {
 	 * Configure a {@link MessageHeaderInitializer} to apply to the headers of
 	 * {@link Message}s from decoded STOMP frames.
 	 */
-	public void setHeaderInitializer(MessageHeaderInitializer headerInitializer) {
+	public void setHeaderInitializer(@Nullable MessageHeaderInitializer headerInitializer) {
 		this.headerInitializer = headerInitializer;
 	}
 

spring-messaging/src/main/java/org/springframework/messaging/simp/stomp/StompHeaderAccessor.java

@@ -246,7 +246,7 @@ public class StompHeaderAccessor extends SimpMessageHeaderAccessor {
 		return (rawValue != null ? StringUtils.commaDelimitedListToSet(rawValue) : Collections.emptySet());
 	}
 
-	public void setHost(String host) {
+	public void setHost(@Nullable String host) {
 		setNativeHeader(STOMP_HOST_HEADER, host);
 	}
 
@@ -302,7 +302,7 @@ public class StompHeaderAccessor extends SimpMessageHeaderAccessor {
 		setNativeHeader(STOMP_HEARTBEAT_HEADER, cx + "," + cy);
 	}
 
-	public void setAck(String ack) {
+	public void setAck(@Nullable String ack) {
 		setNativeHeader(STOMP_ACK_HEADER, ack);
 	}
 
@@ -311,7 +311,7 @@ public class StompHeaderAccessor extends SimpMessageHeaderAccessor {
 		return getFirstNativeHeader(STOMP_ACK_HEADER);
 	}
 
-	public void setNack(String nack) {
+	public void setNack(@Nullable String nack) {
 		setNativeHeader(STOMP_NACK_HEADER, nack);
 	}
 
@@ -320,7 +320,7 @@ public class StompHeaderAccessor extends SimpMessageHeaderAccessor {
 		return getFirstNativeHeader(STOMP_NACK_HEADER);
 	}
 
-	public void setLogin(String login) {
+	public void setLogin(@Nullable String login) {
 		setNativeHeader(STOMP_LOGIN_HEADER, login);
 	}
 
@@ -329,7 +329,7 @@ public class StompHeaderAccessor extends SimpMessageHeaderAccessor {
 		return getFirstNativeHeader(STOMP_LOGIN_HEADER);
 	}
 
-	public void setPasscode(String passcode) {
+	public void setPasscode(@Nullable String passcode) {
 		setNativeHeader(STOMP_PASSCODE_HEADER, passcode);
 		protectPasscode();
 	}
@@ -351,7 +351,7 @@ public class StompHeaderAccessor extends SimpMessageHeaderAccessor {
 		return (credentials != null ? credentials.passcode : null);
 	}
 
-	public void setReceiptId(String receiptId) {
+	public void setReceiptId(@Nullable String receiptId) {
 		setNativeHeader(STOMP_RECEIPT_ID_HEADER, receiptId);
 	}
 
@@ -360,7 +360,7 @@ public class StompHeaderAccessor extends SimpMessageHeaderAccessor {
 		return getFirstNativeHeader(STOMP_RECEIPT_ID_HEADER);
 	}
 
-	public void setReceipt(String receiptId) {
+	public void setReceipt(@Nullable String receiptId) {
 		setNativeHeader(STOMP_RECEIPT_HEADER, receiptId);
 	}
 
@@ -374,7 +374,7 @@ public class StompHeaderAccessor extends SimpMessageHeaderAccessor {
 		return getFirstNativeHeader(STOMP_MESSAGE_HEADER);
 	}
 
-	public void setMessage(String content) {
+	public void setMessage(@Nullable String content) {
 		setNativeHeader(STOMP_MESSAGE_HEADER, content);
 	}
 
@@ -383,7 +383,7 @@ public class StompHeaderAccessor extends SimpMessageHeaderAccessor {
 		return getFirstNativeHeader(STOMP_MESSAGE_ID_HEADER);
 	}
 
-	public void setMessageId(String id) {
+	public void setMessageId(@Nullable String id) {
 		setNativeHeader(STOMP_MESSAGE_ID_HEADER, id);
 	}
 
@@ -392,7 +392,7 @@ public class StompHeaderAccessor extends SimpMessageHeaderAccessor {
 		return getFirstNativeHeader(STOMP_VERSION_HEADER);
 	}
 
-	public void setVersion(String version) {
+	public void setVersion(@Nullable String version) {
 		setNativeHeader(STOMP_VERSION_HEADER, version);
 	}
 

spring-messaging/src/main/java/org/springframework/messaging/simp/stomp/StompHeaders.java

@@ -126,10 +126,15 @@ public class StompHeaders implements MultiValueMap<String, String>, Serializable
 	 * Set the content-type header.
 	 * Applies to the SEND, MESSAGE, and ERROR frames.
 	 */
-	public void setContentType(MimeType mimeType) {
-		Assert.isTrue(!mimeType.isWildcardType(), "'Content-Type' cannot contain wildcard type '*'");
-		Assert.isTrue(!mimeType.isWildcardSubtype(), "'Content-Type' cannot contain wildcard subtype '*'");
-		set(CONTENT_TYPE, mimeType.toString());
+	public void setContentType(@Nullable MimeType mimeType) {
+		if (mimeType != null) {
+			Assert.isTrue(!mimeType.isWildcardType(), "'Content-Type' cannot contain wildcard type '*'");
+			Assert.isTrue(!mimeType.isWildcardSubtype(), "'Content-Type' cannot contain wildcard subtype '*'");
+			set(CONTENT_TYPE, mimeType.toString());
+		}
+		else {
+			set(CONTENT_TYPE, null);
+		}
 	}
 
 	/**
@@ -161,7 +166,7 @@ public class StompHeaders implements MultiValueMap<String, String>, Serializable
 	 * Set the receipt header.
 	 * Applies to any client frame other than CONNECT.
 	 */
-	public void setReceipt(String receipt) {
+	public void setReceipt(@Nullable String receipt) {
 		set(RECEIPT, receipt);
 	}
 
@@ -177,7 +182,7 @@ public class StompHeaders implements MultiValueMap<String, String>, Serializable
 	 * Set the host header.
 	 * Applies to the CONNECT frame.
 	 */
-	public void setHost(String host) {
+	public void setHost(@Nullable String host) {
 		set(HOST, host);
 	}
 
@@ -193,7 +198,7 @@ public class StompHeaders implements MultiValueMap<String, String>, Serializable
 	 * Set the login header.
 	 * Applies to the CONNECT frame.
 	 */
-	public void setLogin(String login) {
+	public void setLogin(@Nullable String login) {
 		set(LOGIN, login);
 	}
 
@@ -209,7 +214,7 @@ public class StompHeaders implements MultiValueMap<String, String>, Serializable
 	 * Set the passcode header.
 	 * Applies to the CONNECT frame.
 	 */
-	public void setPasscode(String passcode) {
+	public void setPasscode(@Nullable String passcode) {
 		set(PASSCODE, passcode);
 	}
 
@@ -263,7 +268,7 @@ public class StompHeaders implements MultiValueMap<String, String>, Serializable
 	 * Set the session header.
 	 * Applies to the CONNECTED frame.
 	 */
-	public void setSession(String session) {
+	public void setSession(@Nullable String session) {
 		set(SESSION, session);
 	}
 
@@ -279,7 +284,7 @@ public class StompHeaders implements MultiValueMap<String, String>, Serializable
 	 * Set the server header.
 	 * Applies to the CONNECTED frame.
 	 */
-	public void setServer(String server) {
+	public void setServer(@Nullable String server) {
 		set(SERVER, server);
 	}
 
@@ -295,7 +300,7 @@ public class StompHeaders implements MultiValueMap<String, String>, Serializable
 	/**
 	 * Set the destination header.
 	 */
-	public void setDestination(String destination) {
+	public void setDestination(@Nullable String destination) {
 		set(DESTINATION, destination);
 	}
 
@@ -312,7 +317,7 @@ public class StompHeaders implements MultiValueMap<String, String>, Serializable
 	 * Set the id header.
 	 * Applies to the SUBSCR0BE, UNSUBSCRIBE, and ACK or NACK frames.
 	 */
-	public void setId(String id) {
+	public void setId(@Nullable String id) {
 		set(ID, id);
 	}
 
@@ -328,7 +333,7 @@ public class StompHeaders implements MultiValueMap<String, String>, Serializable
 	 * Set the ack header to one of "auto", "client", or "client-individual".
 	 * Applies to the SUBSCRIBE and MESSAGE frames.
 	 */
-	public void setAck(String ack) {
+	public void setAck(@Nullable String ack) {
 		set(ACK, ack);
 	}
 
@@ -344,7 +349,7 @@ public class StompHeaders implements MultiValueMap<String, String>, Serializable
 	 * Set the login header.
 	 * Applies to the MESSAGE frame.
 	 */
-	public void setSubscription(String subscription) {
+	public void setSubscription(@Nullable String subscription) {
 		set(SUBSCRIPTION, subscription);
 	}
 
@@ -360,7 +365,7 @@ public class StompHeaders implements MultiValueMap<String, String>, Serializable
 	 * Set the message-id header.
 	 * Applies to the MESSAGE frame.
 	 */
-	public void setMessageId(String messageId) {
+	public void setMessageId(@Nullable String messageId) {
 		set(MESSAGE_ID, messageId);
 	}
 
@@ -376,7 +381,7 @@ public class StompHeaders implements MultiValueMap<String, String>, Serializable
 	 * Set the receipt-id header.
 	 * Applies to the RECEIPT frame.
 	 */
-	public void setReceiptId(String receiptId) {
+	public void setReceiptId(@Nullable String receiptId) {
 		set(RECEIPT_ID, receiptId);
 	}
 
@@ -433,7 +438,7 @@ public class StompHeaders implements MultiValueMap<String, String>, Serializable
 	 * @see #add(String, String)
 	 */
 	@Override
-	public void set(String headerName, String headerValue) {
+	public void set(String headerName, @Nullable String headerValue) {
 		List<String> headerValues = new LinkedList<>();
 		headerValues.add(headerValue);
 		headers.put(headerName, headerValues);

spring-messaging/src/main/java/org/springframework/messaging/simp/user/UserDestinationMessageHandler.java

@@ -108,7 +108,7 @@ public class UserDestinationMessageHandler implements MessageHandler, SmartLifec
 	 * <p>By default this is not set.
 	 * @param destination the target destination.
 	 */
-	public void setBroadcastDestination(String destination) {
+	public void setBroadcastDestination(@Nullable String destination) {
 		this.broadcastHandler = (StringUtils.hasText(destination) ?
 				new BroadcastHandler(this.messagingTemplate, destination) : null);
 	}
@@ -134,7 +134,7 @@ public class UserDestinationMessageHandler implements MessageHandler, SmartLifec
 	 * headers of resolved target messages.
 	 * <p>By default this is not set.
 	 */
-	public void setHeaderInitializer(MessageHeaderInitializer headerInitializer) {
+	public void setHeaderInitializer(@Nullable MessageHeaderInitializer headerInitializer) {
 		this.headerInitializer = headerInitializer;
 	}
 

spring-messaging/src/main/java/org/springframework/messaging/support/IdTimestampMessageHeaderInitializer.java

@@ -43,7 +43,7 @@ public class IdTimestampMessageHeaderInitializer implements MessageHeaderInitial
 	 * IdGenerator of {@link org.springframework.messaging.MessageHeaders} is used.
 	 * <p>To have no id's generated at all, see {@link #setDisableIdGeneration()}.
 	 */
-	public void setIdGenerator(IdGenerator idGenerator) {
+	public void setIdGenerator(@Nullable IdGenerator idGenerator) {
 		this.idGenerator = idGenerator;
 	}