Add support for AnnotatedType in MethodParameter.hasNullableAnnotation

This commit adds support for detecting annotated types.

See gh-28797

spring-core/src/main/java/org/springframework/core/MethodParameter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2023 the original author or authors.
+ * Copyright 2002-2024 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.
@@ -18,6 +18,7 @@ package org.springframework.core;
 
 import java.lang.annotation.Annotation;
 import java.lang.reflect.AnnotatedElement;
+import java.lang.reflect.AnnotatedType;
 import java.lang.reflect.Constructor;
 import java.lang.reflect.Executable;
 import java.lang.reflect.Field;
@@ -388,8 +389,8 @@ public class MethodParameter {
 	/**
 	 * Return whether this method indicates a parameter which is not required:
 	 * either in the form of Java 8's {@link java.util.Optional}, any variant
-	 * of a parameter-level {@code Nullable} annotation (such as from JSR-305
+	 * of a parameter-level {@code Nullable} annotation (such as from JSpecify,
-	 * or the FindBugs set of annotations), or a language-level nullable type
+	 * JSR-305 or Jakarta set of annotations), or a language-level nullable type
 	 * declaration or {@code Continuation} parameter in Kotlin.
 	 * @since 4.3
 	 */
@@ -402,8 +403,8 @@ public class MethodParameter {
 
 	/**
 	 * Check whether this method parameter is annotated with any variant of a
-	 * {@code Nullable} annotation, for example, {@code jakarta.annotation.Nullable} or
+	 * {@code Nullable} annotation, for example, {@code org.springframework.lang.Nullable},
-	 * {@code edu.umd.cs.findbugs.annotations.Nullable}.
+	 * {@code org.jspecify.annotations.Nullable} or {@code jakarta.annotation.Nullable}.
 	 */
 	private boolean hasNullableAnnotation() {
 		for (Annotation ann : getParameterAnnotations()) {
@@ -411,6 +412,13 @@ public class MethodParameter {
 				return true;
 			}
 		}
+		for (AnnotatedType annotatedType : this.executable.getAnnotatedParameterTypes()) {
+			for (Annotation ann : annotatedType.getAnnotations()) {
+				if ("Nullable".equals(ann.annotationType().getSimpleName())) {
+					return true;
+				}
+			}
+		}
 		return false;
 	}
 

spring-core/src/test/java/org/springframework/core/MethodParameterTests.java

@@ -49,6 +49,10 @@ class MethodParameterTests {
 
 	private MethodParameter intReturnType;
 
+	private MethodParameter jspecifyNullableParameter;
+
+	private MethodParameter springNullableParameter;
+
 
 	@BeforeEach
 	void setup() throws NoSuchMethodException {
@@ -56,6 +60,10 @@ class MethodParameterTests {
 		stringParameter = new MethodParameter(method, 0);
 		longParameter = new MethodParameter(method, 1);
 		intReturnType = new MethodParameter(method, -1);
+		Method jspecifyNullableMethod = getClass().getMethod("jspecifyNullableMethod", String.class);
+		jspecifyNullableParameter = new MethodParameter(jspecifyNullableMethod, 0);
+		Method springNullableMethod = getClass().getMethod("springNullableMethod", String.class);
+		springNullableParameter = new MethodParameter(springNullableMethod, 0);
 	}
 
 
@@ -238,21 +246,29 @@ class MethodParameterTests {
 	}
 
 	@Test
-	void nullableWithSpringAnnotation() {
+	void jspecifyNullableParameter() {
-		MethodParameter m = MethodParameter.forExecutable(method, 1);
+		assertThat(jspecifyNullableParameter.isOptional()).isTrue();
-		assertThat(m.isOptional()).isTrue();
 	}
 
 	@Test
-	void nullableWithJSpecifyAnnotation() {
+	void springNullableParameter() {
-		MethodParameter m = MethodParameter.forExecutable(method, 0);
+		assertThat(springNullableParameter.isOptional()).isTrue();
-		assertThat(m.isOptional()).isTrue();
 	}
 
-	public int method(@org.jspecify.annotations.Nullable String p1, @org.springframework.lang.Nullable long p2) {
+	public int method(String p1, long p2) {
 		return 42;
 	}
 
+	public @org.jspecify.annotations.Nullable String jspecifyNullableMethod(@org.jspecify.annotations.Nullable String parameter) {
+		return parameter;
+	}
+
+	@SuppressWarnings("deprecation")
+	@org.springframework.lang.Nullable
+	public String springNullableMethod(@org.springframework.lang.Nullable String parameter) {
+		return parameter;
+	}
+
 	@SuppressWarnings("unused")
 	private static class NestedClass {