Add kafka4-migration module: Spring Kafka 3.3 to 4.1 migration on Boot 3.5 to 4.1

Co-Authored-By: Claude Sonnet 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01Gth99spB1CzQmBFofXmU4Z

kafka4-migration/output/01-legacy-kafka3.txt

@@ -0,0 +1,12 @@
+$ mvn test   # Boot 3.5.16, JDK 21
+RESULT key=k1 id=o-1 qty=3
+BROKERS 127.0.0.1:PORT
+[INFO] Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 7.853 s -- in com.ankurm.kafka.OrderFlowTest
+[INFO] Tests run: 1, Failures: 0, Errors: 0, Skipped: 0
+[INFO] BUILD SUCCESS
+
+org.apache.kafka:kafka-clients:jar:3.9.2:compile
+org.springframework.kafka:spring-kafka:jar:3.3.16:compile
+
+$ java -cp target/classes:<runtime classpath> SerdeProbe
+SERIALIZED {"id":"o-1","qty":3}

kafka4-migration/output/02-boot4-no-starter.txt

@@ -0,0 +1,5 @@
+$ mvn test   # only the Boot version changed to 4.1.1
+[ERROR] Tests run: 1, Failures: 0, Errors: 1, Skipped: 0, Time elapsed: 5.728 s <<< FAILURE! -- in com.ankurm.kafka.OrderFlowTest
+[ERROR]   OrderFlowTest.sendAndReceive ? UnsatisfiedDependency Error creating bean with name 'com.ankurm.kafka.OrderFlowTest': Unsatisfied dependency expressed through field 'template': No qualifying bean of type 'org.springframework.kafka.core.KafkaTemplate<java.lang.String, com.ankurm.kafka.OrderEvent>' available: expected at 
+[ERROR] Tests run: 1, Failures: 0, Errors: 1, Skipped: 0
+[INFO] BUILD FAILURE

kafka4-migration/output/03-starter-added-tests-pass.txt

@@ -0,0 +1,15 @@
+$ mvn test   # spring-kafka replaced by spring-boot-starter-kafka; nothing else changed
+RESULT key=k1 id=o-1 qty=3
+BROKERS localhost:PORT
+[INFO] Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 9.853 s -- in com.ankurm.kafka.OrderFlowTest
+[INFO] Tests run: 1, Failures: 0, Errors: 0, Skipped: 0
+[INFO] BUILD SUCCESS
+
+org.apache.kafka:kafka-clients:jar:4.2.1:compile
+org.springframework.boot:spring-boot-kafka:jar:4.1.1:compile
+org.springframework.kafka:spring-kafka:jar:4.1.1:compile
+
+$ mvn dependency:list | grep jackson   # runtime scope, then test scope
+runtime: tools.jackson.core:jackson-core:jar:3.1.5:compile
+runtime: tools.jackson.core:jackson-databind:jar:3.1.5:compile
+test-only: com.fasterxml.jackson.core:jackson-databind:jar:2.21.5:test

kafka4-migration/output/04-runtime-classpath-has-no-jackson2.txt

@@ -0,0 +1,3 @@
+$ compile and run SerdeProbe on the runtime classpath only (JsonSerializer from Spring Kafka 4.1.1)
+[ERROR]   class file for com.fasterxml.jackson.core.type.TypeReference not found
+[ERROR] s2/src/main/java/com/ankurm/kafka/SerdeProbe.java:[9,45] cannot access com.fasterxml.jackson.core.type.TypeReference

kafka4-migration/output/05-migrated.txt

@@ -0,0 +1,13 @@
+$ mvn test   # final migrated project (JacksonJsonSerializer, spring-boot-starter-jackson)
+RESULT key=k1 id=o-1 qty=3
+BROKERS localhost:PORT
+[INFO] Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 8.478 s -- in com.ankurm.kafka.OrderFlowTest
+[INFO] Tests run: 1, Failures: 0, Errors: 0, Skipped: 0
+[INFO] BUILD SUCCESS
+
+org.apache.kafka:kafka-clients:jar:4.2.1:compile
+org.springframework.boot:spring-boot-kafka:jar:4.1.1:compile
+org.springframework.kafka:spring-kafka:jar:4.1.1:compile
+
+$ java -cp target/classes:<runtime classpath> SerdeProbe
+SERIALIZED {"id":"o-1","qty":3}

kafka4-migration/output/06-serializer-classes.txt

@@ -0,0 +1,2 @@
+$ jar tf spring-kafka-4.1.1.jar | grep support/serializer/(Json|Jackson)
+JacksonJsonDeserializer.class JacksonJsonSerde.class JacksonJsonSerializer.class JacksonJsonTypeResolver.class JsonDeserializer.class JsonSerde.class JsonSerializer.class JsonTypeResolver.class