Find annotations on anonymous classes in AnnotationsUtils.findAnnotat…

…ion()

See spring-projectsgh-28896

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

@@ -23,12 +23,15 @@
 import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;
 import java.lang.reflect.Proxy;
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 import java.util.NoSuchElementException;
+import java.util.Objects;
 import java.util.Set;
+import java.util.stream.Stream;
 
 import org.springframework.core.BridgeMethodResolver;
 import org.springframework.core.annotation.AnnotationTypeMapping.MirrorSets.MirrorSet;
@@ -561,6 +564,18 @@ public static <A extends Annotation> A findAnnotation(Class<?> clazz, @Nullable
 			return null;
 		}
 
+		// check if we are dealing with an annotation on an anonymous class (no need for class hierarchy traversal)
+		final A annotationOnAnonymous = Stream
+				.concat(Stream.of(clazz.getAnnotatedSuperclass()), Arrays.stream(clazz.getAnnotatedInterfaces()))
+				.filter(Objects::nonNull)
+				.map(a -> findAnnotation(a, annotationType))
+				.filter(Objects::nonNull)
+				.findFirst()
+				.orElse(null);
+		if (annotationOnAnonymous != null) {
+			return annotationOnAnonymous;
+		}
+
 		// Shortcut: directly present on the element, with no merging needed?
 		if (AnnotationFilter.PLAIN.matches(annotationType) ||
 				AnnotationsScanner.hasPlainJavaAnnotationsOnly(clazz)) {

spring-core/src/test/java/org/springframework/core/annotation/AnnotationUtilsTests.java

@@ -16,8 +16,10 @@
 
 package org.springframework.core.annotation;
 
+import java.io.Serializable;
 import java.lang.annotation.Annotation;
 import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
 import java.lang.annotation.Inherited;
 import java.lang.annotation.Repeatable;
 import java.lang.annotation.Retention;
@@ -986,6 +988,21 @@ void findDeprecatedAnnotation() throws Exception {
 		assertThat(findAnnotation(SubclassOfDeprecatedClass.class, Deprecated.class)).isNotNull();
 	}
 
+	@Test
+	void findAnnotationOnAnonymousClassWithSuperclass() {
+		assertThat(findAnnotation((new @TypeUseAnnotation Object() {}).getClass(), TypeUseAnnotation.class)).isNotNull();
+		assertThat(findAnnotation((new @TypeUseAnnotation MetaMetaAnnotatedClass() {}).getClass(), TypeUseAnnotation.class)).isNotNull();
+		assertThat(findAnnotation((new Object() {}).getClass(), TypeUseAnnotation.class)).isNull();
+		assertThat(findAnnotation((new MetaMetaAnnotatedClass() {}).getClass(), TypeUseAnnotation.class)).isNull();
+	}
+
+	@Test
+	void findAnnotationOnAnonymousClassWithInterface() {
+		assertThat(findAnnotation((new @TypeUseAnnotation Serializable() {}).getClass(), TypeUseAnnotation.class)).isNotNull();
+		assertThat(findAnnotation((new @TypeUseAnnotation InterfaceWithMetaAnnotation() {}).getClass(), TypeUseAnnotation.class)).isNotNull();
+		assertThat(findAnnotation((new Serializable() {}).getClass(), TypeUseAnnotation.class)).isNull();
+		assertThat(findAnnotation((new InterfaceWithMetaAnnotation() {}).getClass(), TypeUseAnnotation.class)).isNull();
+	}
 
 	@SafeVarargs
 	static <T> T[] asArray(T... arr) {
@@ -1835,4 +1852,8 @@ static class DeprecatedClass {
 	static class SubclassOfDeprecatedClass extends DeprecatedClass {
 	}
 
+	@Target(ElementType.TYPE_USE)
+	@Retention(RetentionPolicy.RUNTIME)
+	@interface TypeUseAnnotation {
+	}
 }