Merge branch '5.3.x'

# Conflicts:
#	spring-core/src/test/java/org/springframework/core/annotation/MergedAnnotationsTests.java

spring-core/src/main/java/org/springframework/core/annotation/AliasFor.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2022 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.
@@ -173,7 +173,7 @@ import java.lang.annotation.Target;
  * @author Sam Brannen
  * @since 4.2
  * @see MergedAnnotations
- * @see SynthesizedAnnotation
+ * @see AnnotationUtils#isSynthesizedAnnotation(Annotation)
  */
 @Retention(RetentionPolicy.RUNTIME)
 @Target(ElementType.METHOD)

spring-core/src/main/java/org/springframework/core/annotation/AnnotationConfigurationException.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2022 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.
@@ -25,7 +25,7 @@ import org.springframework.core.NestedRuntimeException;
  * @author Sam Brannen
  * @since 4.2
  * @see AnnotationUtils
- * @see SynthesizedAnnotation
+ * @see AnnotationUtils#isSynthesizedAnnotation(java.lang.annotation.Annotation)
  */
 @SuppressWarnings("serial")
 public class AnnotationConfigurationException extends NestedRuntimeException {

spring-core/src/main/java/org/springframework/core/annotation/AnnotationUtils.java

@@ -1185,7 +1185,7 @@ public abstract class AnnotationUtils {
 	public static <A extends Annotation> A synthesizeAnnotation(
 			A annotation, @Nullable AnnotatedElement annotatedElement) {
 
-		if (annotation instanceof SynthesizedAnnotation || AnnotationFilter.PLAIN.matches(annotation)) {
+		if (isSynthesizedAnnotation(annotation) || AnnotationFilter.PLAIN.matches(annotation)) {
 			return annotation;
 		}
 		return MergedAnnotation.from(annotatedElement, annotation).synthesize();
@@ -1279,6 +1279,18 @@ public abstract class AnnotationUtils {
 		return synthesized;
 	}
 
+	/**
+	 * Determine if the supplied {@link Annotation} has been <em>synthesized</em>
+	 * by Spring (i.e. wrapped in a dynamic proxy) with additional functionality
+	 * such as attribute alias handling.
+	 * @param annotation the annotation to check
+	 * @return {@code true} if the supplied annotation is a synthesized annotation
+	 * @since 5.3.23
+	 */
+	public static boolean isSynthesizedAnnotation(@Nullable Annotation annotation) {
+		return (annotation instanceof SynthesizedAnnotation);
+	}
+
 	/**
 	 * Clear the internal annotation metadata cache.
 	 * @since 4.3.15