Refine null-safety in the spring-beans module

Closes gh-34152

Author: sdeleuze

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

@@ -98,7 +98,8 @@ public class PropertyEditorRegistrySupport implements PropertyEditorRegistry {
 
 	private boolean configValueEditorsActive = false;
 
-	private @Nullable Map<Class<?>, PropertyEditor> defaultEditors;
+	@SuppressWarnings("NullAway.Init")
+	private Map<Class<?>, PropertyEditor> defaultEditors;
 
 	private @Nullable Map<Class<?>, PropertyEditor> overriddenDefaultEditors;
 
@@ -171,7 +172,6 @@ public void overrideDefaultEditor(Class<?> requiredType, PropertyEditor property
 	 * @return the default editor, or {@code null} if none found
 	 * @see #registerDefaultEditors
 	 */
-	@SuppressWarnings("NullAway")
 	public @Nullable PropertyEditor getDefaultEditor(Class<?> requiredType) {
 		if (!this.defaultEditorsActive) {
 			return null;

spring-beans/src/main/java/org/springframework/beans/factory/BeanDefinitionStoreException.java

@@ -100,9 +100,11 @@ public BeanDefinitionStoreException(@Nullable String resourceDescription, String
 	 * @param cause the root cause (may be {@code null})
 	 */
 	public BeanDefinitionStoreException(
-			@Nullable String resourceDescription, String beanName, String msg, @Nullable Throwable cause) {
+			@Nullable String resourceDescription, String beanName, @Nullable String msg, @Nullable Throwable cause) {
 
-		super("Invalid bean definition with name '" + beanName + "' defined in " + resourceDescription + ": " + msg,
+		super(msg == null ?
+						"Invalid bean definition with name '" + beanName + "' defined in " + resourceDescription :
+						"Invalid bean definition with name '" + beanName + "' defined in " + resourceDescription + ": " + msg,
 				cause);
 		this.resourceDescription = resourceDescription;
 		this.beanName = beanName;

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

@@ -74,7 +74,8 @@ public abstract class AbstractFactoryBean<T>
 
 	private boolean initialized = false;
 
-	private @Nullable T singletonInstance;
+	@SuppressWarnings("NullAway.Init")
+	private T singletonInstance;
 
 	private @Nullable T earlySingletonInstance;
 
@@ -146,7 +147,6 @@ public void afterPropertiesSet() throws Exception {
 	 * @see #getEarlySingletonInterfaces()
 	 */
 	@Override
-	@SuppressWarnings("NullAway")
 	public final T getObject() throws Exception {
 		if (isSingleton()) {
 			return (this.initialized ? this.singletonInstance : getEarlySingletonInstance());

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

@@ -224,7 +224,6 @@ public void setBeanFactory(BeanFactory beanFactory) {
 		this.beanFactory = beanFactory;
 	}
 
-	@SuppressWarnings("NullAway")
 	protected void doProcessProperties(ConfigurableListableBeanFactory beanFactoryToProcess,
 			StringValueResolver valueResolver) {
 

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

@@ -89,13 +89,15 @@ public class PropertyPathFactoryBean implements FactoryBean<Object>, BeanNameAwa
 
 	private @Nullable BeanWrapper targetBeanWrapper;
 
-	private @Nullable String targetBeanName;
+	@SuppressWarnings("NullAway.Init")
+	private String targetBeanName;
 
 	private @Nullable String propertyPath;
 
 	private @Nullable Class<?> resultType;
 
-	private @Nullable String beanName;
+	@SuppressWarnings("NullAway.Init")
+	private String beanName;
 
 	private @Nullable BeanFactory beanFactory;
 
@@ -156,7 +158,6 @@ public void setBeanName(String beanName) {
 
 
 	@Override
-	@SuppressWarnings("NullAway")
 	public void setBeanFactory(BeanFactory beanFactory) {
 		this.beanFactory = beanFactory;
 

spring-beans/src/main/java/org/springframework/beans/factory/groovy/GroovyBeanDefinitionReader.java

@@ -696,7 +696,7 @@ else if (this.currentBeanDefinition != null) {
 		}
 	}
 
-	@SuppressWarnings("NullAway")
+	@SuppressWarnings("NullAway") // Dataflow analysis limitation
 	private GroovyDynamicElementReader createDynamicElementReader(String namespace) {
 		XmlReaderContext readerContext = this.groovyDslXmlBeanDefinitionReader.createReaderContext(
 				new DescriptiveResource("Groovy"));

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

@@ -131,7 +131,7 @@ public ConstructorResolver(AbstractAutowireCapableBeanFactory beanFactory) {
 	 * or {@code null} if none (-> use constructor argument values from bean definition)
 	 * @return a BeanWrapper for the new instance
 	 */
-	@SuppressWarnings("NullAway")
+	@SuppressWarnings("NullAway") // Dataflow analysis limitation
 	public BeanWrapper autowireConstructor(String beanName, RootBeanDefinition mbd,
 			Constructor<?> @Nullable [] chosenCtors, @Nullable Object @Nullable [] explicitArgs) {
 
@@ -393,7 +393,7 @@ private boolean isStaticCandidate(Method method, Class<?> factoryClass) {
 	 * method, or {@code null} if none (-> use constructor argument values from bean definition)
 	 * @return a BeanWrapper for the new instance
 	 */
-	@SuppressWarnings("NullAway")
+	@SuppressWarnings("NullAway") // Dataflow analysis limitation
 	public BeanWrapper instantiateUsingFactoryMethod(
 			String beanName, RootBeanDefinition mbd, @Nullable Object @Nullable [] explicitArgs) {
 

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

@@ -1499,7 +1499,7 @@ else if (descriptor.supportsLazyResolution()) {
 		return doResolveDependency(descriptor, requestingBeanName, autowiredBeanNames, typeConverter);
 	}
 
-	@SuppressWarnings("NullAway")
+	@SuppressWarnings("NullAway") // Dataflow analysis limitation
 	public @Nullable Object doResolveDependency(DependencyDescriptor descriptor, @Nullable String beanName,
 			@Nullable Set<String> autowiredBeanNames, @Nullable TypeConverter typeConverter) throws BeansException {
 

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

@@ -234,7 +234,7 @@ public void addSingletonCallback(String beanName, Consumer<Object> singletonCons
 	 * with, if necessary
 	 * @return the registered singleton object
 	 */
-	@SuppressWarnings("NullAway")
+	@SuppressWarnings("NullAway") // Dataflow analysis limitation
 	public Object getSingleton(String beanName, ObjectFactory<?> singletonFactory) {
 		Assert.notNull(beanName, "Bean name must not be null");
 

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

@@ -72,7 +72,7 @@ public boolean isAutowireCandidate(BeanDefinitionHolder bdHolder, DependencyDesc
 	 * Match the given dependency type with its generic type information against the given
 	 * candidate bean definition.
 	 */
-	@SuppressWarnings("NullAway")
+	@SuppressWarnings("NullAway") // Dataflow analysis limitation
 	protected boolean checkGenericTypeMatch(BeanDefinitionHolder bdHolder, DependencyDescriptor descriptor) {
 		ResolvableType dependencyType = descriptor.getResolvableType();
 		if (dependencyType.getType() instanceof Class) {

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

@@ -145,7 +145,7 @@ protected Object instantiateWithMethodInjection(RootBeanDefinition bd, @Nullable
 	}
 
 	@Override
-	@SuppressWarnings("NullAway")
+	@SuppressWarnings("NullAway") // https://github.com/uber/NullAway/issues/1113
 	public Object instantiate(RootBeanDefinition bd, @Nullable String beanName, BeanFactory owner,
 			@Nullable Object factoryBean, Method factoryMethod, @Nullable Object... args) {
 

spring-beans/src/main/java/org/springframework/beans/factory/xml/BeanDefinitionParserDelegate.java

@@ -407,7 +407,6 @@ public BeanDefinitionDefaults getBeanDefinitionDefaults() {
 	 * if there were errors during parse. Errors are reported to the
 	 * {@link org.springframework.beans.factory.parsing.ProblemReporter}.
 	 */
-	@SuppressWarnings("NullAway")
 	public @Nullable BeanDefinitionHolder parseBeanDefinitionElement(Element ele, @Nullable BeanDefinition containingBean) {
 		String id = ele.getAttribute(ID_ATTRIBUTE);
 		String nameAttr = ele.getAttribute(NAME_ATTRIBUTE);
@@ -457,7 +456,8 @@ public BeanDefinitionDefaults getBeanDefinitionDefaults() {
 					}
 				}
 				catch (Exception ex) {
-					error(ex.getMessage(), ele);
+					String message = ex.getMessage();
+					error(message == null ? "" : message, ele);
 					return null;
 				}
 			}