Merge pull request #24415 from valfirst

* pr/24415:
  Polish "Upgrade to Jackson 2.12.0"
  Upgrade to Jackson 2.12.0

Closes gh-24415

Author: snicoll

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

@@ -257,10 +257,8 @@ private void configurePropertyNamingStrategyClass(Jackson2ObjectMapperBuilder bu
 			private void configurePropertyNamingStrategyField(Jackson2ObjectMapperBuilder builder, String fieldName) {
 				// Find the field (this way we automatically support new constants
 				// that may be added by Jackson in the future)
-				Field field = ReflectionUtils.findField(PropertyNamingStrategy.class, fieldName,
-						PropertyNamingStrategy.class);
-				Assert.notNull(field, () -> "Constant named '" + fieldName + "' not found on "
-						+ PropertyNamingStrategy.class.getName());
+				Field field = findPropertyNamingStrategyField(fieldName);
+				Assert.notNull(field, () -> "Constant named '" + fieldName + "' not found");
 				try {
 					builder.propertyNamingStrategy((PropertyNamingStrategy) field.get(null));
 				}
@@ -269,6 +267,17 @@ private void configurePropertyNamingStrategyField(Jackson2ObjectMapperBuilder bu
 				}
 			}
 
+			private Field findPropertyNamingStrategyField(String fieldName) {
+				try {
+					return ReflectionUtils.findField(com.fasterxml.jackson.databind.PropertyNamingStrategies.class,
+							fieldName, PropertyNamingStrategy.class);
+				}
+				catch (NoClassDefFoundError ex) { // Fallback pre Jackson 2.12
+					return ReflectionUtils.findField(PropertyNamingStrategy.class, fieldName,
+							PropertyNamingStrategy.class);
+				}
+			}
+
 			private void configureModules(Jackson2ObjectMapperBuilder builder) {
 				Collection<Module> moduleBeans = getBeans(this.applicationContext, Module.class);
 				builder.modulesToInstall(moduleBeans.toArray(new Module[0]));

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

@@ -50,8 +50,8 @@ public class JacksonProperties {
 	private String dateFormat;
 
 	/**
-	 * One of the constants on Jackson's PropertyNamingStrategy. Can also be a
-	 * fully-qualified class name of a PropertyNamingStrategy subclass.
+	 * One of the constants on Jackson's PropertyNamingStrategies. Can also be a
+	 * fully-qualified class name of a PropertyNamingStrategy implementation.
 	 */
 	private String propertyNamingStrategy;
 

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/jackson/Jackson211AutoConfigurationTests.java

@@ -0,0 +1,57 @@
+/*
+ * Copyright 2012-2020 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.autoconfigure.jackson;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import org.junit.jupiter.api.Test;
+
+import org.springframework.boot.testsupport.classpath.ClassPathExclusions;
+import org.springframework.boot.testsupport.classpath.ClassPathOverrides;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests for {@link JacksonAutoConfiguration} using Jackson 2.11.x
+ *
+ * @author Stephane Nicoll
+ */
+@ClassPathExclusions({ "jackson-databind*.jar", "jackson-dataformat-xml*.jar" })
+@ClassPathOverrides({ "com.fasterxml.jackson.core:jackson-databind:2.11.3",
+		"com.fasterxml.jackson.dataformat:jackson-dataformat-xml:2.11.3" })
+public class Jackson211AutoConfigurationTests extends JacksonAutoConfigurationTests {
+
+	public static final String STRATEGY_CLASS_NAME = "com.fasterxml.jackson.databind.PropertyNamingStrategy$SnakeCaseStrategy";
+
+	@Test
+	void customPropertyNamingStrategyField() {
+		this.contextRunner.withPropertyValues("spring.jackson.property-naming-strategy:SNAKE_CASE").run((context) -> {
+			ObjectMapper mapper = context.getBean(ObjectMapper.class);
+			assertThat(mapper.getPropertyNamingStrategy().getClass().getName()).isEqualTo(STRATEGY_CLASS_NAME);
+		});
+	}
+
+	@Test
+	void customPropertyNamingStrategyClass() {
+		this.contextRunner.withPropertyValues(
+				"spring.jackson.property-naming-strategy:com.fasterxml.jackson.databind.PropertyNamingStrategy.SnakeCaseStrategy")
+				.run((context) -> {
+					ObjectMapper mapper = context.getBean(ObjectMapper.class);
+					assertThat(mapper.getPropertyNamingStrategy().getClass().getName()).isEqualTo(STRATEGY_CLASS_NAME);
+				});
+	}
+
+}

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

@@ -37,7 +37,7 @@
 import com.fasterxml.jackson.databind.MapperFeature;
 import com.fasterxml.jackson.databind.Module;
 import com.fasterxml.jackson.databind.ObjectMapper;
-import com.fasterxml.jackson.databind.PropertyNamingStrategy.SnakeCaseStrategy;
+import com.fasterxml.jackson.databind.PropertyNamingStrategies.SnakeCaseStrategy;
 import com.fasterxml.jackson.databind.SerializationFeature;
 import com.fasterxml.jackson.databind.SerializerProvider;
 import com.fasterxml.jackson.databind.module.SimpleModule;
@@ -72,7 +72,7 @@
  */
 class JacksonAutoConfigurationTests {
 
-	private final ApplicationContextRunner contextRunner = new ApplicationContextRunner()
+	protected final ApplicationContextRunner contextRunner = new ApplicationContextRunner()
 			.withConfiguration(AutoConfigurations.of(JacksonAutoConfiguration.class));
 
 	@Test
@@ -132,7 +132,7 @@ void customPropertyNamingStrategyField() {
 	@Test
 	void customPropertyNamingStrategyClass() {
 		this.contextRunner.withPropertyValues(
-				"spring.jackson.property-naming-strategy:com.fasterxml.jackson.databind.PropertyNamingStrategy.SnakeCaseStrategy")
+				"spring.jackson.property-naming-strategy:com.fasterxml.jackson.databind.PropertyNamingStrategies.SnakeCaseStrategy")
 				.run((context) -> {
 					ObjectMapper mapper = context.getBean(ObjectMapper.class);
 					assertThat(mapper.getPropertyNamingStrategy()).isInstanceOf(SnakeCaseStrategy.class);

spring-boot-project/spring-boot-dependencies/build.gradle

@@ -493,7 +493,7 @@ bom {
 			]
 		}
 	}
-	library("Jackson Bom", "2.11.3") {
+	library("Jackson Bom", "2.12.0") {
 		group("com.fasterxml.jackson") {
 			imports = [
 				"jackson-bom"

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/main/java/org/springframework/boot/buildpack/platform/json/SharedObjectMapper.java

@@ -18,7 +18,7 @@
 
 import com.fasterxml.jackson.databind.DeserializationFeature;
 import com.fasterxml.jackson.databind.ObjectMapper;
-import com.fasterxml.jackson.databind.PropertyNamingStrategy;
+import com.fasterxml.jackson.databind.PropertyNamingStrategies;
 import com.fasterxml.jackson.databind.SerializationFeature;
 import com.fasterxml.jackson.module.paramnames.ParameterNamesModule;
 
@@ -37,7 +37,7 @@ public final class SharedObjectMapper {
 		objectMapper.registerModule(new ParameterNamesModule());
 		objectMapper.enable(SerializationFeature.INDENT_OUTPUT);
 		objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
-		objectMapper.setPropertyNamingStrategy(PropertyNamingStrategy.LOWER_CAMEL_CASE);
+		objectMapper.setPropertyNamingStrategy(PropertyNamingStrategies.LOWER_CAMEL_CASE);
 		INSTANCE = objectMapper;
 	}
 

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/test/java/org/springframework/boot/buildpack/platform/json/SharedObjectMapperTests.java

@@ -18,7 +18,7 @@
 
 import com.fasterxml.jackson.databind.DeserializationFeature;
 import com.fasterxml.jackson.databind.ObjectMapper;
-import com.fasterxml.jackson.databind.PropertyNamingStrategy;
+import com.fasterxml.jackson.databind.PropertyNamingStrategies;
 import com.fasterxml.jackson.databind.SerializationFeature;
 import com.fasterxml.jackson.module.paramnames.ParameterNamesModule;
 import org.junit.jupiter.api.Test;
@@ -42,9 +42,9 @@ void getReturnsConfiguredObjectMapper() {
 		assertThat(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES
 				.enabledIn(mapper.getDeserializationConfig().getDeserializationFeatures())).isFalse();
 		assertThat(mapper.getSerializationConfig().getPropertyNamingStrategy())
-				.isEqualTo(PropertyNamingStrategy.LOWER_CAMEL_CASE);
+				.isEqualTo(PropertyNamingStrategies.LOWER_CAMEL_CASE);
 		assertThat(mapper.getDeserializationConfig().getPropertyNamingStrategy())
-				.isEqualTo(PropertyNamingStrategy.LOWER_CAMEL_CASE);
+				.isEqualTo(PropertyNamingStrategies.LOWER_CAMEL_CASE);
 	}
 
 }