Merge pull request #33080 from ueberfuhr

* pr/33080:
  Polish 'Add reflection hints for PropertyNamingStrategies'
  Add reflection hints for PropertyNamingStrategies

Closes gh-33080

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/jackson/JacksonAutoConfiguration.java

@@ -26,17 +26,22 @@ import java.util.List;
 import java.util.Locale;
 import java.util.Map;
 import java.util.TimeZone;
+import java.util.stream.Stream;
 
 import com.fasterxml.jackson.annotation.JsonAutoDetect;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.PropertyAccessor;
 import com.fasterxml.jackson.databind.Module;
 import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.PropertyNamingStrategies;
 import com.fasterxml.jackson.databind.PropertyNamingStrategy;
 import com.fasterxml.jackson.databind.SerializationFeature;
 import com.fasterxml.jackson.databind.cfg.ConstructorDetector;
 import com.fasterxml.jackson.module.paramnames.ParameterNamesModule;
 
+import org.springframework.aot.hint.ReflectionHints;
+import org.springframework.aot.hint.RuntimeHints;
+import org.springframework.aot.hint.RuntimeHintsRegistrar;
 import org.springframework.beans.BeanUtils;
 import org.springframework.beans.factory.ObjectProvider;
 import org.springframework.boot.autoconfigure.AutoConfiguration;
@@ -75,6 +80,7 @@ import org.springframework.util.ReflectionUtils;
  * @author Johannes Edmeier
  * @author Phillip Webb
  * @author Eddú Meléndez
+ * @author Ralf Ueberfuhr
  * @since 1.1.0
  */
 @AutoConfiguration
@@ -342,4 +348,36 @@ public class JacksonAutoConfiguration {
 
 	}
 
+	static class JacksonAutoConfigurationRuntimeHints implements RuntimeHintsRegistrar {
+
+		@Override
+		public void registerHints(RuntimeHints hints, ClassLoader classLoader) {
+			if (ClassUtils.isPresent("com.fasterxml.jackson.databind.PropertyNamingStrategy", classLoader)) {
+				registerPropertyNamingStrategyHints(hints.reflection());
+			}
+		}
+
+		/**
+		 * Register hints for the {@code configurePropertyNamingStrategyField} method to
+		 * use.
+		 * @param hints reflection hints
+		 */
+		private void registerPropertyNamingStrategyHints(ReflectionHints hints) {
+			registerPropertyNamingStrategyHints(hints, PropertyNamingStrategies.class);
+			// PropertyNamingStrategy is used pre Jackson 2.12
+			registerPropertyNamingStrategyHints(hints, PropertyNamingStrategy.class);
+		}
+
+		private void registerPropertyNamingStrategyHints(ReflectionHints hints, Class<?> type) {
+			Stream.of(type.getDeclaredFields()).filter(this::isPropertyNamingStrategyField)
+					.forEach(hints::registerField);
+		}
+
+		private boolean isPropertyNamingStrategyField(Field candidate) {
+			return ReflectionUtils.isPublicStaticFinal(candidate)
+					&& candidate.getType().isAssignableFrom(PropertyNamingStrategy.class);
+		}
+
+	}
+
 }

spring-boot-project/spring-boot-autoconfigure/src/main/resources/META-INF/spring/aot.factories

@@ -1,4 +1,5 @@
 org.springframework.aot.hint.RuntimeHintsRegistrar=\
+org.springframework.boot.autoconfigure.jackson.JacksonAutoConfiguration.JacksonAutoConfigurationRuntimeHints,\
 org.springframework.boot.autoconfigure.template.TemplateRuntimeHints
 
 org.springframework.beans.factory.aot.BeanFactoryInitializationAotProcessor=\

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/jackson/JacksonAutoConfigurationTests.java

@@ -23,6 +23,7 @@ import java.time.Duration;
 import java.util.Date;
 import java.util.HashSet;
 import java.util.Set;
+import java.util.stream.Stream;
 
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonCreator.Mode;
@@ -38,7 +39,9 @@ import com.fasterxml.jackson.databind.JsonSerializer;
 import com.fasterxml.jackson.databind.MapperFeature;
 import com.fasterxml.jackson.databind.Module;
 import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.PropertyNamingStrategies;
 import com.fasterxml.jackson.databind.PropertyNamingStrategies.SnakeCaseStrategy;
+import com.fasterxml.jackson.databind.PropertyNamingStrategy;
 import com.fasterxml.jackson.databind.SerializationFeature;
 import com.fasterxml.jackson.databind.SerializerProvider;
 import com.fasterxml.jackson.databind.cfg.ConstructorDetector;
@@ -50,10 +53,14 @@ import com.fasterxml.jackson.module.paramnames.ParameterNamesModule;
 import org.assertj.core.api.InstanceOfAssertFactories;
 import org.junit.jupiter.api.Test;
 
+import org.springframework.aot.hint.RuntimeHints;
+import org.springframework.aot.hint.predicate.ReflectionHintsPredicates;
+import org.springframework.aot.hint.predicate.RuntimeHintsPredicates;
 import org.springframework.beans.factory.BeanCurrentlyInCreationException;
 import org.springframework.boot.autoconfigure.AutoConfigurationPackage;
 import org.springframework.boot.autoconfigure.AutoConfigurations;
 import org.springframework.boot.autoconfigure.http.HttpMessageConvertersAutoConfiguration;
+import org.springframework.boot.autoconfigure.jackson.JacksonAutoConfiguration.JacksonAutoConfigurationRuntimeHints;
 import org.springframework.boot.jackson.JsonComponent;
 import org.springframework.boot.jackson.JsonMixin;
 import org.springframework.boot.jackson.JsonMixinModule;
@@ -81,6 +88,7 @@ import static org.mockito.Mockito.mock;
  * @author Sebastien Deleuze
  * @author Johannes Edmeier
  * @author Grzegorz Poznachowski
+ * @author Ralf Ueberfuhr
  */
 class JacksonAutoConfigurationTests {
 
@@ -456,6 +464,22 @@ class JacksonAutoConfigurationTests {
 		});
 	}
 
+	@Test
+	void shouldRegisterPropertyNamingStrategyHints() {
+		shouldRegisterPropertyNamingStrategyHints(PropertyNamingStrategies.class, "LOWER_CAMEL_CASE",
+				"UPPER_CAMEL_CASE", "SNAKE_CASE", "UPPER_SNAKE_CASE", "LOWER_CASE", "KEBAB_CASE", "LOWER_DOT_CASE");
+		shouldRegisterPropertyNamingStrategyHints(PropertyNamingStrategy.class, "LOWER_CAMEL_CASE", "UPPER_CAMEL_CASE",
+				"SNAKE_CASE", "LOWER_CASE", "KEBAB_CASE", "LOWER_DOT_CASE");
+	}
+
+	private void shouldRegisterPropertyNamingStrategyHints(Class<?> type, String... fieldNames) {
+		RuntimeHints hints = new RuntimeHints();
+		new JacksonAutoConfigurationRuntimeHints().registerHints(hints, getClass().getClassLoader());
+		ReflectionHintsPredicates reflection = RuntimeHintsPredicates.reflection();
+		Stream.of(fieldNames).map((name) -> reflection.onField(type, name))
+				.forEach((predicate) -> assertThat(predicate).accepts(hints));
+	}
+
 	private void assertParameterNamesModuleCreatorBinding(Mode expectedMode, Class<?>... configClasses) {
 		this.contextRunner.withUserConfiguration(configClasses).run((context) -> {
 			DeserializationConfig deserializationConfig = context.getBean(ObjectMapper.class)