Refine reflection hints handling for anonymous class

Before this commit, anonymous classes could throw an
unexpected NullPointerException in
ReflectionsHint#registerType and lambdas entries could
be created in the related generated reflect-config.json.

This commit refines how anonymous classes are handled by
explicitly checking for null class and canonical name in
ReflectionTypeReference#of, while skipping such class in
ReflectionHints#registerType in order to keep a lenient
behavior.

Closes gh-29774

spring-core/src/test/java/org/springframework/aot/hint/ReflectionHintsTests.java

@@ -34,6 +34,7 @@ import static org.mockito.Mockito.verifyNoInteractions;
  * Tests for {@link ReflectionHints}.
  *
  * @author Stephane Nicoll
+ * @author Sebastien Deleuze
  */
 class ReflectionHintsTests {
 
@@ -132,6 +133,16 @@ class ReflectionHintsTests {
 				assertThat(fieldHint.getName()).isEqualTo("field"));
 	}
 
+	@Test
+	void registerTypeIgnoresLambda() {
+		Runnable lambda = () -> { };
+		Consumer<TypeHint.Builder> hintBuilder = mock();
+		this.reflectionHints.registerType(lambda.getClass());
+		this.reflectionHints.registerType(lambda.getClass(), hintBuilder);
+		assertThat(this.reflectionHints.typeHints()).isEmpty();
+		verifyNoInteractions(hintBuilder);
+	}
+
 	private void assertTestTypeFieldHint(Consumer<FieldHint> fieldHint) {
 		assertThat(this.reflectionHints.typeHints()).singleElement().satisfies(typeHint -> {
 			assertThat(typeHint.getType().getCanonicalName()).isEqualTo(TestType.class.getCanonicalName());

spring-core/src/test/java/org/springframework/aot/hint/ReflectionTypeReferenceTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2023 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.
@@ -18,11 +18,13 @@ package org.springframework.aot.hint;
 
 import java.util.stream.Stream;
 
+import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.Arguments;
 import org.junit.jupiter.params.provider.MethodSource;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
 import static org.junit.jupiter.params.provider.Arguments.arguments;
 
 /**
@@ -30,9 +32,21 @@ import static org.junit.jupiter.params.provider.Arguments.arguments;
  *
  * @author Stephane Nicoll
  * @author Moritz Halbritter
+ * @author Sebastien Deleuze
  */
 class ReflectionTypeReferenceTests {
 
+	@Test
+	void typeReferenceWithNullClass() {
+		assertThatIllegalArgumentException().isThrownBy(() -> ReflectionTypeReference.of(null));
+	}
+
+	@Test
+	void typeReferenceWithLambda() {
+		Runnable lambda = () -> { };
+		assertThatIllegalArgumentException().isThrownBy(() -> ReflectionTypeReference.of(lambda.getClass()));
+	}
+
 	@ParameterizedTest
 	@MethodSource("reflectionTargetNames")
 	void typeReferenceFromClassHasSuitableReflectionTargetName(Class<?> clazz, String binaryName) {

spring-core/src/test/java/org/springframework/aot/nativex/ReflectionHintsWriterTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2023 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.
@@ -201,6 +201,14 @@ public class ReflectionHintsWriterTests {
 				""", hints);
 	}
 
+	@Test
+	void ignoreLambda() throws JSONException {
+		Runnable anonymousRunnable = () -> { };
+		ReflectionHints hints = new ReflectionHints();
+		hints.registerType(anonymousRunnable.getClass());
+		assertEquals("[]", hints);
+	}
+
 	private void assertEquals(String expectedString, ReflectionHints hints) throws JSONException {
 		StringWriter out = new StringWriter();
 		BasicJsonWriter writer = new BasicJsonWriter(out, "\t");