Fix nullability annotations in ReflectionUtils and AnnotationSupport

Author: marcphilipp

junit-platform-commons/src/main/java/org/junit/platform/commons/support/AnnotationSupport.java

@@ -443,7 +443,8 @@ public static List<Field> findAnnotatedFields(Class<?> clazz, Class<? extends An
 	 * @see ReflectionSupport#tryToReadFieldValue(Field, Object)
 	 */
 	@API(status = MAINTAINED, since = "1.4")
-	public static List<Object> findAnnotatedFieldValues(Object instance, Class<? extends Annotation> annotationType) {
+	public static List<@Nullable Object> findAnnotatedFieldValues(Object instance,
+			Class<? extends Annotation> annotationType) {
 		Preconditions.notNull(instance, "instance must not be null");
 
 		List<Field> fields = findAnnotatedFields(instance.getClass(), annotationType, ModifierSupport::isNotStatic,
@@ -475,7 +476,8 @@ public static List<Object> findAnnotatedFieldValues(Object instance, Class<? ext
 	 * @see ReflectionSupport#tryToReadFieldValue(Field, Object)
 	 */
 	@API(status = MAINTAINED, since = "1.4")
-	public static List<Object> findAnnotatedFieldValues(Class<?> clazz, Class<? extends Annotation> annotationType) {
+	public static List<@Nullable Object> findAnnotatedFieldValues(Class<?> clazz,
+			Class<? extends Annotation> annotationType) {
 
 		List<Field> fields = findAnnotatedFields(clazz, annotationType, ModifierSupport::isStatic,
 			HierarchyTraversalMode.TOP_DOWN);
@@ -510,8 +512,8 @@ public static List<Object> findAnnotatedFieldValues(Class<?> clazz, Class<? exte
 	 */
 	@SuppressWarnings("unchecked")
 	@API(status = MAINTAINED, since = "1.4")
-	public static <T> List<T> findAnnotatedFieldValues(Object instance, Class<? extends Annotation> annotationType,
-			Class<T> fieldType) {
+	public static <T extends @Nullable Object> List<T> findAnnotatedFieldValues(Object instance,
+			Class<? extends Annotation> annotationType, Class<T> fieldType) {
 
 		Preconditions.notNull(instance, "instance must not be null");
 		Preconditions.notNull(fieldType, "fieldType must not be null");
@@ -552,8 +554,8 @@ public static <T> List<T> findAnnotatedFieldValues(Object instance, Class<? exte
 	 */
 	@SuppressWarnings("unchecked")
 	@API(status = MAINTAINED, since = "1.4")
-	public static <T> List<T> findAnnotatedFieldValues(Class<?> clazz, Class<? extends Annotation> annotationType,
-			Class<T> fieldType) {
+	public static <T extends @Nullable Object> List<T> findAnnotatedFieldValues(Class<?> clazz,
+			Class<? extends Annotation> annotationType, Class<T> fieldType) {
 
 		Preconditions.notNull(fieldType, "fieldType must not be null");
 

junit-platform-commons/src/main/java/org/junit/platform/commons/util/ReflectionUtils.java

@@ -626,7 +626,7 @@ public static <T> T newInstance(Constructor<T> constructor, @Nullable Object...
 	 * @see #tryToReadFieldValue(Field, Object)
 	 */
 	@API(status = INTERNAL, since = "1.4")
-	public static <T> Try<Object> tryToReadFieldValue(Class<T> clazz, String fieldName, T instance) {
+	public static <T> Try<Object> tryToReadFieldValue(Class<T> clazz, String fieldName, @Nullable T instance) {
 		Preconditions.notNull(clazz, "Class must not be null");
 		Preconditions.notBlank(fieldName, "Field name must not be null or blank");
 
@@ -677,7 +677,7 @@ public static <T> Try<Object> tryToReadFieldValue(Class<T> clazz, String fieldNa
 	 * @return an immutable list of the values of the specified fields; never
 	 * {@code null} but may be empty or contain {@code null} entries
 	 */
-	public static List<Object> readFieldValues(List<Field> fields, @Nullable Object instance) {
+	public static List<@Nullable Object> readFieldValues(List<Field> fields, @Nullable Object instance) {
 		return readFieldValues(fields, instance, field -> true);
 	}
 
@@ -694,7 +694,7 @@ public static List<Object> readFieldValues(List<Field> fields, @Nullable Object
 	 * @return an immutable list of the values of the specified fields; never
 	 * {@code null} but may be empty or contain {@code null} entries
 	 */
-	public static List<Object> readFieldValues(List<Field> fields, @Nullable Object instance,
+	public static List<@Nullable Object> readFieldValues(List<Field> fields, @Nullable Object instance,
 			Predicate<Field> predicate) {
 		Preconditions.notNull(fields, "fields list must not be null");
 		Preconditions.notNull(predicate, "Predicate must not be null");