Add support for Jackson annotations in BindingReflectionHintsRegistrar

This commits registers reflection hints on field and methods
where Jackson annotations are detected.

Closes gh-29426

spring-core/spring-core.gradle

@@ -84,6 +84,8 @@ dependencies {
 	testImplementation("io.projectreactor.tools:blockhound")
 	testImplementation("org.skyscreamer:jsonassert")
 	testImplementation("com.squareup.okhttp3:mockwebserver")
+	testImplementation("org.jetbrains.kotlinx:kotlinx-serialization-json")
+	testImplementation("com.fasterxml.jackson.core:jackson-annotations")
 	testFixturesImplementation("com.google.code.findbugs:jsr305")
 	testFixturesImplementation("org.junit.platform:junit-platform-launcher")
 	testFixturesImplementation("org.junit.jupiter:junit-jupiter-api")
@@ -91,7 +93,6 @@ dependencies {
 	testFixturesImplementation("org.assertj:assertj-core")
 	testFixturesImplementation("org.xmlunit:xmlunit-assertj")
 	testFixturesImplementation("io.projectreactor:reactor-test")
-	testImplementation("org.jetbrains.kotlinx:kotlinx-serialization-json")
 }
 
 jar {

spring-core/src/main/java/org/springframework/aot/hint/BindingReflectionHintsRegistrar.java

@@ -16,6 +16,7 @@
 
 package org.springframework.aot.hint;
 
+import java.lang.reflect.Field;
 import java.lang.reflect.Method;
 import java.lang.reflect.RecordComponent;
 import java.lang.reflect.Type;
@@ -28,8 +29,11 @@ import kotlin.reflect.KClass;
 import org.springframework.core.KotlinDetector;
 import org.springframework.core.MethodParameter;
 import org.springframework.core.ResolvableType;
+import org.springframework.core.annotation.MergedAnnotation;
+import org.springframework.core.annotation.MergedAnnotations;
 import org.springframework.lang.Nullable;
 import org.springframework.util.ClassUtils;
+import org.springframework.util.ReflectionUtils;
 
 /**
  * Register the necessary reflection hints so that the specified type can be
@@ -45,6 +49,11 @@ public class BindingReflectionHintsRegistrar {
 
 	private static final String KOTLIN_COMPANION_SUFFIX = "$Companion";
 
+	private static final String JACKSON_ANNOTATION = "com.fasterxml.jackson.annotation.JacksonAnnotation";
+
+	private static final boolean jacksonAnnotationPresent = ClassUtils.isPresent(JACKSON_ANNOTATION,
+			BindingReflectionHintsRegistrar.class.getClassLoader());
+
 	/**
 	 * Register the necessary reflection hints to bind the specified types.
 	 * @param hints the hints instance to use
@@ -97,6 +106,9 @@ public class BindingReflectionHintsRegistrar {
 							}
 						}
 					}
+					if (jacksonAnnotationPresent) {
+						registerJacksonHints(hints, clazz);
+					}
 				}
 				if (KotlinDetector.isKotlinType(clazz)) {
 					KotlinDelegate.registerComponentHints(hints, clazz);
@@ -147,6 +159,31 @@ public class BindingReflectionHintsRegistrar {
 		}
 	}
 
+	private void registerJacksonHints(ReflectionHints hints, Class<?> clazz) {
+		ReflectionUtils.doWithFields(clazz, field ->
+				MergedAnnotations
+						.from(field, MergedAnnotations.SearchStrategy.TYPE_HIERARCHY)
+						.stream(JACKSON_ANNOTATION)
+						.filter(MergedAnnotation::isMetaPresent)
+						.forEach(annotation -> {
+							Field sourceField = (Field) annotation.getSource();
+							if (sourceField != null) {
+								hints.registerField(sourceField);
+							}
+						}));
+		ReflectionUtils.doWithMethods(clazz, method ->
+				MergedAnnotations
+						.from(method, MergedAnnotations.SearchStrategy.TYPE_HIERARCHY)
+						.stream(JACKSON_ANNOTATION)
+						.filter(MergedAnnotation::isMetaPresent)
+						.forEach(annotation -> {
+							Method sourceMethod = (Method) annotation.getSource();
+							if (sourceMethod != null) {
+								hints.registerMethod(sourceMethod, ExecutableMode.INVOKE);
+							}
+						}));
+	}
+
 	/**
 	 * Inner class to avoid a hard dependency on Kotlin at runtime.
 	 */

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

@@ -20,8 +20,10 @@ import java.lang.reflect.Type;
 import java.util.List;
 import java.util.Set;
 
+import com.fasterxml.jackson.annotation.JsonProperty;
 import org.junit.jupiter.api.Test;
 
+import org.springframework.aot.hint.predicate.RuntimeHintsPredicates;
 import org.springframework.core.ResolvableType;
 
 import static org.assertj.core.api.Assertions.assertThat;
@@ -219,6 +221,24 @@ public class BindingReflectionHintsRegistrarTests {
 				});
 	}
 
+	@Test
+	void registerTypeForJacksonAnnotations() {
+		bindingRegistrar.registerReflectionHints(this.hints.reflection(), SampleClassWithJsonProperty.class);
+		assertThat(RuntimeHintsPredicates.reflection().onField(SampleClassWithJsonProperty.class, "privateField"))
+				.accepts(this.hints);
+		assertThat(RuntimeHintsPredicates.reflection().onMethod(SampleClassWithJsonProperty.class, "packagePrivateMethod").invoke())
+				.accepts(this.hints);
+	}
+
+	@Test
+	void registerTypeForInheritedJacksonAnnotations() {
+		bindingRegistrar.registerReflectionHints(this.hints.reflection(), SampleClassWithInheritedJsonProperty.class);
+		assertThat(RuntimeHintsPredicates.reflection().onField(SampleClassWithJsonProperty.class, "privateField"))
+				.accepts(this.hints);
+		assertThat(RuntimeHintsPredicates.reflection().onMethod(SampleClassWithJsonProperty.class, "packagePrivateMethod").invoke())
+				.accepts(this.hints);
+	}
+
 
 	static class SampleEmptyClass {
 	}
@@ -291,7 +311,7 @@ public class BindingReflectionHintsRegistrarTests {
 		}
 	}
 
-	class SampleClassC {
+	static class SampleClassC {
 		public String getString() {
 			return "";
 		}
@@ -303,4 +323,17 @@ public class BindingReflectionHintsRegistrarTests {
 
 	record SampleRecord(String name) {}
 
+	static class SampleClassWithJsonProperty {
+
+		@JsonProperty
+		private String privateField = "";
+
+		@JsonProperty
+		String packagePrivateMethod() {
+			return "";
+		}
+	}
+
+	static class SampleClassWithInheritedJsonProperty extends SampleClassWithJsonProperty {}
+
 }