GH-3930: Add Jackson 3 support; deprecate Jackson 2 #3996

sobychacko · 2025-07-17T02:29:57Z

Manage dependencies, similar way we do for Jackson 2
Add Jackson 3 counterparts for existing Jackson 2 based classes (mostly copy/paste)
Deprectate Jackson 2 classes
Update tests
Initial round of updates in docs

artembilan · 2025-07-17T15:13:46Z

...g-kafka/src/main/java/org/springframework/kafka/support/DefaultJacksonKafkaHeaderMapper.java

+	 */
+	public DefaultJacksonKafkaHeaderMapper(String... patterns) {
+		this(JsonMapper.builder()
+				.findAndAddModules(JacksonJsonMessageConverter.class.getClassLoader())


The class loader from this class exactly, not something else to avoid class tangle and so.

artembilan · 2025-07-17T15:14:34Z

...g-kafka/src/main/java/org/springframework/kafka/support/DefaultJacksonKafkaHeaderMapper.java

+	 * Create an instance for inbound mapping only with pattern matching.
+	 * @param patterns the patterns to match.
+	 * @return the header mapper.
+	 * @since 2.8.8


No @since on methods in all new classes, please.

artembilan · 2025-07-17T15:22:57Z

...g-kafka/src/main/java/org/springframework/kafka/support/DefaultJacksonKafkaHeaderMapper.java

+					Object value = decodeValue(header, type);
+					headers.put(header.key(), value);
+				}
+				catch (IOException e) {


This should be revised since Jackson 3 does not throw IOException any more.
May just catch (Exception e) { instead?

artembilan · 2025-07-17T15:24:22Z

...rc/main/java/org/springframework/kafka/support/converter/BatchMessagingMessageConverter.java

@@ -101,6 +103,9 @@ public BatchMessagingMessageConverter(@Nullable RecordMessageConverter recordCon
 		if (JacksonPresent.isJackson2Present()) {
 			this.headerMapper = new DefaultKafkaHeaderMapper();
 		}
+		else if (JacksonPresent.isJackson3Present()) {


Let's prefer Jackson 3!
If they have both in classpath, so Jackson 3 choice would win.

...a/src/main/java/org/springframework/kafka/support/converter/JacksonJsonMessageConverter.java

artembilan · 2025-07-17T15:29:41Z

...a/src/main/java/org/springframework/kafka/support/converter/JacksonJsonMessageConverter.java

+
+	private JacksonJavaTypeMapper typeMapper = new DefaultJacksonJavaTypeMapper();
+
+	private final TypeFactory typeFactory = TypeFactory.createDefaultInstance();


Let's use ObjectMapper.getTypeFactory() instead in the ctor!

artembilan · 2025-07-17T15:32:30Z

...main/java/org/springframework/kafka/support/converter/JacksonProjectingMessageConverter.java

+import org.springframework.util.Assert;
+
+/**
+ * A {@link MessageConverter} implementation based on Jacthat uses a Spring Data


You probably meant based on Jackson 3 😄

artembilan · 2025-07-17T15:52:54Z

build.gradle

@@ -263,6 +265,13 @@ project ('spring-kafka') {
 			exclude group: 'org.jetbrains.kotlin'
 		}

+		optionalApi 'tools.jackson.core:jackson-databind'
+		optionalApi 'tools.jackson.datatype:jackson-datatype-joda'
+		optionalApi 'tools.jackson.dataformat:jackson-dataformat-xml'


We don't do XML here in Spring Kafka, so let's just remove this redundant dependency!

Fixes spring-projects#3930 Issue link: spring-projects#3930 This commit introduces comprehensive Jackson 3 support across the Spring for Apache Kafka framework while maintaining backward compatibility by deprecating Jackson 2 components. BREAKING CHANGES: - All Jackson 2-based classes are now deprecated and will be removed in a future version - Default Jackson version updated from 2.19.2 to 2.19.1 for Jackson 2 - Added Jackson 3 BOM dependency (3.0.0-rc5) NEW FEATURES: - Added complete Jackson 3 counterparts for all existing Jackson 2 classes: * JsonKafkaHeaderMapper (replaces DefaultKafkaHeaderMapper) * JacksonJsonSerializer/Deserializer (replaces JsonSerializer/Deserializer) * JacksonJsonSerde (replaces JsonSerde) * JacksonJsonMessageConverter and subclasses (replaces JsonMessageConverter family) * JacksonProjectingMessageConverter (replaces ProjectingMessageConverter) * DefaultJacksonJavaTypeMapper (replaces DefaultJackson2JavaTypeMapper) * Jackson3Utils and Jackson3MimeTypeModule utilities INFRASTRUCTURE: - Enhanced JacksonPresent utility to detect Jackson 3 availability - Updated MessagingMessageConverter and BatchMessagingMessageConverter to prefer Jackson 3 - Modified RecordMessagingMessageListenerAdapter to handle new converter types - Updated all serialization/deserialization logic to use Jackson 3 APIs DOCUMENTATION: - Updated all documentation references from Jackson 2 to Jackson 3 classes - Corrected sample code and configuration examples - Updated method signatures and class references throughout documentation TESTING: - Migrated all test cases to use Jackson 3 equivalents - Updated test configurations and mock setups - Maintained test coverage for both Jackson 2 (deprecated) and Jackson 3 paths The framework now automatically detects and prefers Jackson 3 when available, falling back to Jackson 2 for backward compatibility. All existing applications will continue to work with Jackson 2, but new development should migrate to Jackson 3 classes. Signed-off-by: Soby Chacko <[email protected]>

artembilan

FYI: spring-projects/spring-framework#35282.

Might be the case that we can do that already in your current incarnation.

artembilan

I think whats-new deserves a dedicated bullet for Jackson 3.
Thanks

artembilan · 2025-08-12T17:30:15Z

build.gradle

@@ -55,7 +55,8 @@ ext {
 	awaitilityVersion = '4.3.0'
 	hamcrestVersion = '3.0'
 	hibernateValidationVersion = '9.0.1.Final'
-	jacksonBomVersion = '2.19.2'
+	jacksonBomVersion = '2.19.1'


Why downgrade?

artembilan · 2025-08-12T17:32:50Z

spring-kafka/src/main/java/org/springframework/kafka/support/Jackson3Utils.java

+				.enable(SerializationFeature.FAIL_ON_EMPTY_BEANS)
+				.addModule(new Jackson3MimeTypeModule())
+				.build();
+		return objectMapper;


Why do we need local variable?
Why cannot we just use return forthe builder result?

artembilan · 2025-08-12T17:33:25Z

spring-kafka/src/main/java/org/springframework/kafka/support/Jackson3Utils.java

+	 * {@link DeserializationFeature#FAIL_ON_UNKNOWN_PROPERTIES} features.
+	 * @return the {@link ObjectMapper} instance.
+	 */
+	public static ObjectMapper enhancedObjectMapper() {


See my general comment.
Apparently we have to be as specific as possible.
And make this as JsonMapper instead.

artembilan · 2025-08-12T17:34:13Z

spring-kafka/src/main/java/org/springframework/kafka/support/JacksonUtils.java

@@ -29,7 +29,10 @@
 * @author Artem Bilan
 *
 * @since 2.3
+ *
+ * @deprecated since 4.0 in favor of native Jackson 3 {@link tools.jackson.databind.json.JsonMapper#builder()} API.


And now this is not correct since you have just introduced Jackson3Utils.

artembilan · 2025-08-12T17:37:12Z

spring-kafka/src/main/java/org/springframework/kafka/support/Jackson3Utils.java

+ *
+ * @since 4.0
+ */
+public final class Jackson3Utils {


The name is not what is required from the framework perspective.
The goal is to avoid numbers as much as possible.
How about to name this class as JacksonMapperUtils instead?

artembilan · 2025-08-12T17:38:41Z

spring-kafka/src/main/java/org/springframework/kafka/support/JacksonMimeTypeModule.java

@@ -31,6 +31,8 @@
 * @author Artem Bilan
 *
 * @since 2.3
+ *
+ * @deprecated since 4.0 in favor of {@link Jackson3Utils}.


Not correct link.
And class is not marked with @Deprecated.

artembilan · 2025-08-12T17:39:47Z

spring-kafka/src/main/java/org/springframework/kafka/support/Jackson3MimeTypeModule.java

+ *
+ * @since 4.0
+ */
+public final class Jackson3MimeTypeModule extends SimpleModule {


How about MimeTypeJacksonModule instead?
Just to avoid that number!

artembilan · 2025-08-12T17:43:04Z

...fka/src/main/java/org/springframework/kafka/support/converter/MessagingMessageConverter.java

@@ -94,6 +96,9 @@ public MessagingMessageConverter(Function<Message<?>, @Nullable Integer> partiti
 		if (JacksonPresent.isJackson2Present()) {
 			this.headerMapper = new DefaultKafkaHeaderMapper();
 		}
+		else if (JacksonPresent.isJackson3Present()) {


I think Jackson 3 has to be in priority if both are on classpath.

artembilan · 2025-08-12T17:47:38Z

spring-kafka/src/main/java/org/springframework/kafka/support/JsonKafkaHeaderMapper.java

@@ -0,0 +1,485 @@
+/*
+ * Copyright 2017-present the original author or authors.


And no this is not right.
This class was not started back in that year.
Just nit-picking thought, since I know that Spring Boot uses a year of the project beginning for everything 🤷

artembilan · 2025-08-13T17:22:14Z

FYI, the refinement has already happened in Spring AMQP: spring-projects/spring-amqp#3151.

The fix might be useful to follow here as well.

@deprecated

This commit refines the Jackson 3 implementation introduced in the previous commit to improve API consistency and naming conventions. CHANGES: - Rename Jackson3Utils to JacksonMapperUtils for better naming consistency - Rename Jackson3MimeTypeModule to MimeTypeJacksonModule to follow Spring conventions - Update all Jackson 3 classes to use JsonMapper instead of ObjectMapper for type safety - Restore Jackson 2 BOM version from 2.19.1 to 2.19.2 - Prioritize Jackson 3 over Jackson 2 in MessagingMessageConverter detection - Add a section in whats-new for Jackson 3 changes TECHNICAL IMPROVEMENTS: - Enhanced type safety by using JsonMapper (Jackson 3) instead of generic ObjectMapper - Consistent naming patterns across all Jackson 3 components - Updated method names: getObjectMapper() → getJsonMapper() - Updated parameter names: objectMapper → jsonMapper throughout codebase - Updated factory method: enhancedObjectMapper() → jsonMapper() API CHANGES: - All Jackson 3 constructors now accept JsonMapper instead of ObjectMapper - JsonKafkaHeaderMapper uses JsonMapper for better type consistency - JacksonProjectingMessageConverter updated to use JsonMapper API - All serializer/deserializer classes consistently use JsonMapper DEPRECATION UPDATES: - Updated deprecation messages to reference correct replacement classes - Added missing @deprecated annotation to JacksonMimeTypeModule This refinement aligns with Spring Framework's approach to Jackson 3 integration and ensures a clean, consistent API surface for the new Jackson 3 support. Related: spring-projects/spring-framework#35282 Signed-off-by: Soby Chacko <[email protected]>

artembilan · 2025-08-13T20:40:15Z

spring-kafka/src/main/java/org/springframework/kafka/support/JacksonMapperUtils.java

+	 * {@link DeserializationFeature#FAIL_ON_UNKNOWN_PROPERTIES} features.
+	 * @return the {@link JsonMapper} instance.
+	 */
+	public static JsonMapper jsonMapper() {


Why cannot we call enhanced any more?

Signed-off-by: Soby Chacko <[email protected]>

artembilan requested changes Jul 17, 2025

View reviewed changes

sobychacko force-pushed the gh-3930 branch from 5f54304 to 1dc4575 Compare August 11, 2025 23:45

artembilan requested changes Aug 12, 2025

View reviewed changes

artembilan requested changes Aug 13, 2025

View reviewed changes

Restore enhancedJsonMapper method name

5b4a37e

Signed-off-by: Soby Chacko <[email protected]>

artembilan merged commit c5787dc into spring-projects:main Aug 14, 2025
3 checks passed


		private JacksonJavaTypeMapper typeMapper = new DefaultJacksonJavaTypeMapper();

		private final TypeFactory typeFactory = TypeFactory.createDefaultInstance();

		@@ -0,0 +1,485 @@
		/*
		* Copyright 2017-present the original author or authors.

GH-3930: Add Jackson 3 support; deprecate Jackson 2 #3996

GH-3930: Add Jackson 3 support; deprecate Jackson 2 #3996

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sobychacko commented Jul 17, 2025

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artembilan commented Aug 13, 2025

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