Nullability refinements and related polishing

See gh-32475

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

@@ -364,18 +364,18 @@ public static Object invokeJoinpointUsingReflection(@Nullable Object target, Met
 		}
 	}
 
+
 	/**
 	 * Inner class to avoid a hard dependency on Kotlin at runtime.
 	 */
 	private static class KotlinDelegate {
 
-		public static Publisher<?> invokeSuspendingFunction(Method method, Object target, Object... args) {
+		public static Publisher<?> invokeSuspendingFunction(Method method, @Nullable Object target, Object... args) {
 			Continuation<?> continuation = (Continuation<?>) args[args.length -1];
 			Assert.state(continuation != null, "No Continuation available");
 			CoroutineContext context = continuation.getContext().minusKey(Job.Key);
 			return CoroutinesUtils.invokeSuspendingFunction(context, method, target, args);
 		}
-
 	}
 
 }

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2023 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -845,8 +845,10 @@ protected AbstractNestablePropertyAccessor getPropertyAccessorForPropertyPath(St
 	 * @return the PropertyAccessor instance, either cached or newly created
 	 */
 	private AbstractNestablePropertyAccessor getNestedPropertyAccessor(String nestedProperty) {
-		if (this.nestedPropertyAccessors == null) {
-			this.nestedPropertyAccessors = new HashMap<>();
+		Map<String, AbstractNestablePropertyAccessor> nestedAccessors = this.nestedPropertyAccessors;
+		if (nestedAccessors == null) {
+			nestedAccessors = new HashMap<>();
+			this.nestedPropertyAccessors = nestedAccessors;
 		}
 		// Get value of bean property.
 		PropertyTokenHolder tokens = getPropertyNameTokens(nestedProperty);
@@ -862,7 +864,7 @@ private AbstractNestablePropertyAccessor getNestedPropertyAccessor(String nested
 		}
 
 		// Lookup cached sub-PropertyAccessor, create new one if not found.
-		AbstractNestablePropertyAccessor nestedPa = this.nestedPropertyAccessors.get(canonicalName);
+		AbstractNestablePropertyAccessor nestedPa = nestedAccessors.get(canonicalName);
 		if (nestedPa == null || nestedPa.getWrappedInstance() != ObjectUtils.unwrapOptional(value)) {
 			if (logger.isTraceEnabled()) {
 				logger.trace("Creating new nested " + getClass().getSimpleName() + " for property '" + canonicalName + "'");
@@ -871,7 +873,7 @@ private AbstractNestablePropertyAccessor getNestedPropertyAccessor(String nested
 			// Inherit all type-specific PropertyEditors.
 			copyDefaultEditorsTo(nestedPa);
 			copyCustomEditorsTo(nestedPa, canonicalName);
-			this.nestedPropertyAccessors.put(canonicalName, nestedPa);
+			nestedAccessors.put(canonicalName, nestedPa);
 		}
 		else {
 			if (logger.isTraceEnabled()) {

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2023 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -54,6 +54,7 @@
 import org.springframework.core.io.Resource;
 import org.springframework.core.io.support.EncodedResource;
 import org.springframework.lang.Nullable;
+import org.springframework.util.Assert;
 import org.springframework.util.ObjectUtils;
 import org.springframework.util.StringUtils;
 
@@ -250,6 +251,7 @@ public int loadBeanDefinitions(EncodedResource encodedResource) throws BeanDefin
 		@SuppressWarnings("serial")
 		Closure<Object> beans = new Closure<>(this) {
 			@Override
+			@Nullable
 			public Object call(Object... args) {
 				invokeBeanDefiningClosure((Closure<?>) args[0]);
 				return null;
@@ -425,6 +427,7 @@ else if (args.length > 1 && args[args.length -1] instanceof Closure) {
 
 	private boolean addDeferredProperty(String property, Object newValue) {
 		if (newValue instanceof List || newValue instanceof Map) {
+			Assert.state(this.currentBeanDefinition != null, "No current bean definition set");
 			this.deferredProperties.put(this.currentBeanDefinition.getBeanName() + '.' + property,
 					new DeferredProperty(this.currentBeanDefinition, property, newValue));
 			return true;
@@ -640,6 +643,7 @@ else if (value instanceof Closure<?> callable) {
 				this.currentBeanDefinition = current;
 			}
 		}
+		Assert.state(this.currentBeanDefinition != null, "No current bean definition set");
 		this.currentBeanDefinition.addProperty(name, value);
 	}
 
@@ -654,6 +658,7 @@ else if (value instanceof Closure<?> callable) {
 	 * </ul>
 	 */
 	@Override
+	@Nullable
 	public Object getProperty(String name) {
 		Binding binding = getBinding();
 		if (binding != null && binding.hasVariable(name)) {
@@ -727,9 +732,10 @@ private static class DeferredProperty {
 
 		private final String name;
 
+		@Nullable
 		public Object value;
 
-		public DeferredProperty(GroovyBeanDefinitionWrapper beanDefinition, String name, Object value) {
+		public DeferredProperty(GroovyBeanDefinitionWrapper beanDefinition, String name, @Nullable Object value) {
 			this.beanDefinition = beanDefinition;
 			this.name = name;
 			this.value = value;
@@ -762,20 +768,18 @@ public MetaClass getMetaClass() {
 		}
 
 		@Override
+		@Nullable
 		public Object getProperty(String property) {
 			if (property.equals("beanName")) {
 				return getBeanName();
 			}
 			else if (property.equals("source")) {
 				return getSource();
 			}
-			else if (this.beanDefinition != null) {
+			else {
 				return new GroovyPropertyValue(
 						property, this.beanDefinition.getBeanDefinition().getPropertyValues().get(property));
 			}
-			else {
-				return this.metaClass.getProperty(this, property);
-			}
 		}
 
 		@Override
@@ -804,9 +808,10 @@ private class GroovyPropertyValue extends GroovyObjectSupport {
 
 			private final String propertyName;
 
+			@Nullable
 			private final Object propertyValue;
 
-			public GroovyPropertyValue(String propertyName, Object propertyValue) {
+			public GroovyPropertyValue(String propertyName, @Nullable Object propertyValue) {
 				this.propertyName = propertyName;
 				this.propertyValue = propertyValue;
 			}

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2023 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -84,7 +84,7 @@ class GroovyBeanDefinitionWrapper extends GroovyObjectSupport {
 		this(beanName, clazz, null);
 	}
 
-	GroovyBeanDefinitionWrapper(@Nullable String beanName, Class<?> clazz, @Nullable Collection<?> constructorArgs) {
+	GroovyBeanDefinitionWrapper(@Nullable String beanName, @Nullable Class<?> clazz, @Nullable Collection<?> constructorArgs) {
 		this.beanName = beanName;
 		this.clazz = clazz;
 		this.constructorArgs = constructorArgs;
@@ -130,11 +130,12 @@ void setBeanDefinitionHolder(BeanDefinitionHolder holder) {
 	}
 
 	BeanDefinitionHolder getBeanDefinitionHolder() {
-		return new BeanDefinitionHolder(getBeanDefinition(), getBeanName());
+		Assert.state(this.beanName != null, "Bean name must be set");
+		return new BeanDefinitionHolder(getBeanDefinition(), this.beanName);
 	}
 
-	void setParent(Object obj) {
-		Assert.notNull(obj, "Parent bean cannot be set to a null runtime bean reference.");
+	void setParent(@Nullable Object obj) {
+		Assert.notNull(obj, "Parent bean cannot be set to a null runtime bean reference");
 		if (obj instanceof String name) {
 			this.parentName = name;
 		}
@@ -148,7 +149,7 @@ else if (obj instanceof GroovyBeanDefinitionWrapper wrapper) {
 		getBeanDefinition().setAbstract(false);
 	}
 
-	GroovyBeanDefinitionWrapper addProperty(String propertyName, Object propertyValue) {
+	GroovyBeanDefinitionWrapper addProperty(String propertyName, @Nullable Object propertyValue) {
 		if (propertyValue instanceof GroovyBeanDefinitionWrapper wrapper) {
 			propertyValue = wrapper.getBeanDefinition();
 		}
@@ -158,6 +159,7 @@ GroovyBeanDefinitionWrapper addProperty(String propertyName, Object propertyValu
 
 
 	@Override
+	@Nullable
 	public Object getProperty(String property) {
 		Assert.state(this.definitionWrapper != null, "BeanDefinition wrapper not initialized");
 		if (this.definitionWrapper.isReadableProperty(property)) {
@@ -170,7 +172,7 @@ else if (dynamicProperties.contains(property)) {
 	}
 
 	@Override
-	public void setProperty(String property, Object newValue) {
+	public void setProperty(String property, @Nullable Object newValue) {
 		if (PARENT.equals(property)) {
 			setParent(newValue);
 		}

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2023 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -638,7 +638,7 @@ boolean hasAnyExternallyManagedDestroyMethod(String destroyMethod) {
 		}
 	}
 
-	private static boolean hasAnyExternallyManagedMethod(Set<String> candidates, String methodName) {
+	private static boolean hasAnyExternallyManagedMethod(@Nullable Set<String> candidates, String methodName) {
 		if (candidates != null) {
 			for (String candidate : candidates) {
 				int indexOfDot = candidate.lastIndexOf('.');

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2021 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -126,9 +126,10 @@ protected void doRegisterBeanDefinitions(Element root) {
 		// then ultimately reset this.delegate back to its original (parent) reference.
 		// this behavior emulates a stack of delegates without actually necessitating one.
 		BeanDefinitionParserDelegate parent = this.delegate;
-		this.delegate = createDelegate(getReaderContext(), root, parent);
+		BeanDefinitionParserDelegate current = createDelegate(getReaderContext(), root, parent);
+		this.delegate = current;
 
-		if (this.delegate.isDefaultNamespace(root)) {
+		if (current.isDefaultNamespace(root)) {
 			String profileSpec = root.getAttribute(PROFILE_ATTRIBUTE);
 			if (StringUtils.hasText(profileSpec)) {
 				String[] specifiedProfiles = StringUtils.tokenizeToStringArray(
@@ -146,7 +147,7 @@ protected void doRegisterBeanDefinitions(Element root) {
 		}
 
 		preProcessXml(root);
-		parseBeanDefinitions(root, this.delegate);
+		parseBeanDefinitions(root, current);
 		postProcessXml(root);
 
 		this.delegate = parent;

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2023 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -1096,7 +1096,13 @@ public Object executeSynchronized(CacheOperationInvoker invoker, Method method,
 				}
 			}
 			if (KotlinDetector.isKotlinReflectPresent() && KotlinDetector.isSuspendingFunction(method)) {
-				return Mono.fromFuture(cache.retrieve(key, () -> ((Mono<?>) invokeOperation(invoker)).toFuture()));
+				return Mono.fromFuture(cache.retrieve(key, () -> {
+					Mono<?> mono = ((Mono<?>) invokeOperation(invoker));
+					if (mono == null) {
+						mono = Mono.empty();
+					}
+					return mono.toFuture();
+				}));
 			}
 			return NOT_HANDLED;
 		}

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2023 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -78,12 +78,13 @@ public Object invoke(final MethodInvocation invocation) throws Throwable {
 		}
 	}
 
+
 	/**
 	 * Inner class to avoid a hard dependency on Kotlin at runtime.
 	 */
 	private static class KotlinDelegate {
 
-		public static Publisher<?> invokeSuspendingFunction(Method method, Object target, Object... args) {
+		public static Publisher<?> invokeSuspendingFunction(Method method, @Nullable Object target, Object... args) {
 			Continuation<?> continuation = (Continuation<?>) args[args.length - 1];
 			CoroutineContext coroutineContext = continuation.getContext().minusKey(Job.Key);
 			return CoroutinesUtils.invokeSuspendingFunction(coroutineContext, method, target, args);

spring-context/src/main/java/org/springframework/context/aot/AbstractAotProcessor.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -257,6 +257,7 @@ public Builder classOutput(Path classOutput) {
 			 * @return this builder for method chaining
 			 */
 			public Builder groupId(String groupId) {
+				Assert.hasText(groupId, "'groupId' must not be empty");
 				this.groupId = groupId;
 				return this;
 			}
@@ -268,6 +269,7 @@ public Builder groupId(String groupId) {
 			 * @return this builder for method chaining
 			 */
 			public Builder artifactId(String artifactId) {
+				Assert.hasText(artifactId, "'artifactId' must not be empty");
 				this.artifactId = artifactId;
 				return this;
 			}
@@ -279,14 +281,12 @@ public Settings build() {
 				Assert.notNull(this.sourceOutput, "'sourceOutput' must not be null");
 				Assert.notNull(this.resourceOutput, "'resourceOutput' must not be null");
 				Assert.notNull(this.classOutput, "'classOutput' must not be null");
-				Assert.hasText(this.groupId, "'groupId' must not be null or empty");
-				Assert.hasText(this.artifactId, "'artifactId' must not be null or empty");
+				Assert.notNull(this.groupId, "'groupId' must not be null");
+				Assert.notNull(this.artifactId, "'artifactId' must not be null");
 				return new Settings(this.sourceOutput, this.resourceOutput, this.classOutput,
 						this.groupId, this.artifactId);
 			}
-
 		}
-
 	}
 
 }

spring-context/src/main/java/org/springframework/context/event/ApplicationListenerMethodAdapter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2023 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -318,8 +318,8 @@ else if (result instanceof org.springframework.util.concurrent.ListenableFuture<
 		}
 	}
 
-	private void publishEvents(Object result) {
-		if (result.getClass().isArray()) {
+	private void publishEvents(@Nullable Object result) {
+		if (result != null && result.getClass().isArray()) {
 			Object[] events = ObjectUtils.toObjectArray(result);
 			for (Object event : events) {
 				publishEvent(event);

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -83,18 +83,21 @@ public void setBeanClassLoader(ClassLoader classLoader) {
 	public void afterPropertiesSet() throws MBeanServerNotFoundException, MBeanInfoRetrievalException {
 		super.afterPropertiesSet();
 
+		Class<?> interfaceToUse;
 		if (this.proxyInterface == null) {
-			this.proxyInterface = getManagementInterface();
-			if (this.proxyInterface == null) {
+			interfaceToUse = getManagementInterface();
+			if (interfaceToUse == null) {
 				throw new IllegalArgumentException("Property 'proxyInterface' or 'managementInterface' is required");
 			}
+			this.proxyInterface = interfaceToUse;
 		}
 		else {
+			interfaceToUse = this.proxyInterface;
 			if (getManagementInterface() == null) {
-				setManagementInterface(this.proxyInterface);
+				setManagementInterface(interfaceToUse);
 			}
 		}
-		this.mbeanProxy = new ProxyFactory(this.proxyInterface, this).getProxy(this.beanClassLoader);
+		this.mbeanProxy = new ProxyFactory(interfaceToUse, this).getProxy(this.beanClassLoader);
 	}