Return null for getSuperClassName() with package-info classes

Update `ClassFileClassMetadata` to align the behavior of
`getSuperClassName()` with other readers in that it returns
`null` for `package-info` classes.

See gh-34869

spring-core/src/main/java24/org/springframework/core/type/classreading/ClassFileClassMetadata.java

@@ -72,7 +72,7 @@ class ClassFileClassMetadata implements AnnotationMetadata {
 		this.className = className;
 		this.accessFlags = accessFlags;
 		this.enclosingClassName = enclosingClassName;
-		this.superClassName = superClassName;
+		this.superClassName = (!className.endsWith(".package-info")) ? superClassName : null;
 		this.independentInnerClass = independentInnerClass;
 		this.interfaceNames = interfaceNames;
 		this.memberClassNames = memberClassNames;

spring-core/src/test/java/org/springframework/core/type/AbstractAnnotationMetadataTests.java

@@ -161,6 +161,12 @@ public abstract class AbstractAnnotationMetadataTests {
 			assertThat(get(TestSubInterface.class).getSuperClassName()).isIn(null, "java.lang.Object");
 		}
 
+		@Test
+		void getSuperClassNameWhenPackageInfoReturnsNull() throws Exception {
+			Class<?> packageClass = Class.forName(getClass().getPackageName() + ".package-info");
+			assertThat(get(packageClass).getSuperClassName()).isNull();
+		}
+
 		@Test
 		void getInterfaceNamesWhenHasInterfacesReturnsNames() {
 			assertThat(get(TestSubclass.class).getInterfaceNames()).containsExactly(TestInterface.class.getName());

spring-core/src/test/java/org/springframework/core/type/classreading/DefaultAnnotationMetadataTests.java

@@ -0,0 +1,42 @@
+/*
+ * Copyright 2002-2025 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.core.type.classreading;
+
+import org.springframework.core.type.AbstractAnnotationMetadataTests;
+import org.springframework.core.type.AnnotationMetadata;
+
+/**
+ * Tests for {@link SimpleAnnotationMetadata} and
+ * {@link SimpleAnnotationMetadataReadingVisitor} on Java < 24,
+ * and for the ClassFile API variant on Java >= 24.
+ *
+ * @author Phillip Webb
+ */
+class DefaultAnnotationMetadataTests extends AbstractAnnotationMetadataTests {
+
+	@Override
+	protected AnnotationMetadata get(Class<?> source) {
+		try {
+			return MetadataReaderFactory.create(source.getClassLoader())
+					.getMetadataReader(source.getName()).getAnnotationMetadata();
+		}
+		catch (Exception ex) {
+			throw new IllegalStateException(ex);
+		}
+	}
+
+}

spring-core/src/test/java/org/springframework/core/type/classreading/SimpleAnnotationMetadataTests.java

@@ -21,8 +21,7 @@ import org.springframework.core.type.AnnotationMetadata;
 
 /**
  * Tests for {@link SimpleAnnotationMetadata} and
- * {@link SimpleAnnotationMetadataReadingVisitor} on Java < 24,
- * and for the ClassFile API variant on Java >= 24.
+ * {@link SimpleAnnotationMetadataReadingVisitor}.
  *
  * @author Phillip Webb
  */
@@ -31,8 +30,9 @@ class SimpleAnnotationMetadataTests extends AbstractAnnotationMetadataTests {
 	@Override
 	protected AnnotationMetadata get(Class<?> source) {
 		try {
-			return MetadataReaderFactory.create(source.getClassLoader())
-					.getMetadataReader(source.getName()).getAnnotationMetadata();
+			return new SimpleMetadataReaderFactory(
+					source.getClassLoader()).getMetadataReader(
+							source.getName()).getAnnotationMetadata();
 		}
 		catch (Exception ex) {
 			throw new IllegalStateException(ex);