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-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);
 	}
 
 	/**