Fix nullability warnings

Author: jhoeller

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

@@ -16,6 +16,7 @@
 
 package org.springframework.messaging.handler.invocation.reactive;
 
+import java.lang.reflect.Method;
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
@@ -120,7 +121,6 @@ public Mono<Void> handleReturnValue(
 				handleEncodedContent(Flux.from(publisher), returnType, message));
 	}
 
-	@SuppressWarnings("unchecked")
 	private Flux<DataBuffer> encodeContent(
 			@Nullable Object content, MethodParameter returnType, DataBufferFactory bufferFactory,
 			@Nullable MimeType mimeType, Map<String, Object> hints) {
@@ -132,9 +132,10 @@ private Flux<DataBuffer> encodeContent(
 		ResolvableType elementType;
 		if (adapter != null) {
 			publisher = adapter.toPublisher(content);
-			boolean isUnwrapped = KotlinDetector.isSuspendingFunction(returnType.getMethod()) &&
-					!COROUTINES_FLOW_CLASS_NAME.equals(returnValueType.toClass().getName());
-			ResolvableType genericType = isUnwrapped ? returnValueType : returnValueType.getGeneric();
+			Method method = returnType.getMethod();
+			boolean isUnwrapped = (method != null && KotlinDetector.isSuspendingFunction(method) &&
+					!COROUTINES_FLOW_CLASS_NAME.equals(returnValueType.toClass().getName()));
+			ResolvableType genericType = (isUnwrapped ? returnValueType : returnValueType.getGeneric());
 			elementType = getElementType(adapter, genericType);
 		}
 		else {

spring-test/src/main/java/org/springframework/test/context/TestContextAnnotationUtils.java

@@ -75,8 +75,10 @@ public abstract class TestContextAnnotationUtils {
 	private static final ConcurrentLruCache<Class<?>, EnclosingConfiguration> cachedEnclosingConfigurationModes =
 			new ConcurrentLruCache<>(32, TestContextAnnotationUtils::lookUpEnclosingConfiguration);
 
+	@Nullable
 	private static volatile EnclosingConfiguration defaultEnclosingConfigurationMode;
 
+
 	/**
 	 * Find the first annotation of the specified {@code annotationType} within
 	 * the annotation hierarchy <em>above</em> the supplied class, merge that
@@ -411,13 +413,15 @@ private static EnclosingConfiguration lookUpEnclosingConfiguration(Class<?> claz
 	}
 
 	private static EnclosingConfiguration getDefaultEnclosingConfigurationMode() {
-		if (defaultEnclosingConfigurationMode == null) {
+		EnclosingConfiguration defaultConfigurationMode = defaultEnclosingConfigurationMode;
+		if (defaultConfigurationMode == null) {
 			String value = SpringProperties.getProperty(NestedTestConfiguration.ENCLOSING_CONFIGURATION_PROPERTY_NAME);
 			EnclosingConfiguration enclosingConfigurationMode = EnclosingConfiguration.from(value);
-			defaultEnclosingConfigurationMode =
+			defaultConfigurationMode =
 					(enclosingConfigurationMode != null ? enclosingConfigurationMode : EnclosingConfiguration.INHERIT);
+			defaultEnclosingConfigurationMode = defaultConfigurationMode;
 		}
-		return defaultEnclosingConfigurationMode;
+		return defaultConfigurationMode;
 	}
 
 	private static void assertNonEmptyAnnotationTypeArray(Class<?>[] annotationTypes, String message) {
@@ -503,9 +507,10 @@ public static class AnnotationDescriptor<T extends Annotation> {
 			this.declaringClass = declaringClass;
 			this.composedAnnotation = composedAnnotation;
 			this.annotation = annotation;
-			this.annotationAttributes = AnnotatedElementUtils.findMergedAnnotationAttributes(
+			AnnotationAttributes attributes = AnnotatedElementUtils.findMergedAnnotationAttributes(
 					rootDeclaringClass, annotation.annotationType().getName(), false, false);
-			Assert.state(this.annotationAttributes != null, "No annotation attributes");
+			Assert.state(attributes != null, "No annotation attributes");
+			this.annotationAttributes = attributes;
 		}
 
 		public Class<?> getRootDeclaringClass() {

spring-test/src/main/java/org/springframework/test/context/support/TestPropertySourceUtils.java

@@ -126,16 +126,15 @@ else if (!duplicationDetected(currentAttributes, previousAttributes)) {
 	}
 
 	private static boolean duplicationDetected(TestPropertySourceAttributes currentAttributes,
-			TestPropertySourceAttributes previousAttributes) {
+			@Nullable TestPropertySourceAttributes previousAttributes) {
 
 		boolean duplicationDetected =
 				(currentAttributes.equals(previousAttributes) && !currentAttributes.isEmpty());
 
 		if (duplicationDetected && logger.isDebugEnabled()) {
-			logger.debug(String.format("Ignoring duplicate %s declaration on %s, "
-					+ "since it is also declared on %s.", currentAttributes,
-					previousAttributes.getDeclaringClass().getName(),
-					currentAttributes.getDeclaringClass().getName()));
+			logger.debug(String.format("Ignoring duplicate %s declaration on %s since it is also declared on %s",
+					currentAttributes, currentAttributes.getDeclaringClass().getName(),
+					previousAttributes.getDeclaringClass().getName()));
 		}
 
 		return duplicationDetected;

spring-tx/src/main/java/org/springframework/transaction/interceptor/TransactionAspectSupport.java

@@ -851,6 +851,7 @@ private static Object asFlow(Publisher<?> publisher) {
 		}
 
 		@SuppressWarnings("unchecked")
+		@Nullable
 		private static Object awaitSingleOrNull(Publisher<?> publisher, Object continuation) {
 			return AwaitKt.awaitSingleOrNull(publisher, (Continuation<Object>) continuation);
 		}