👀 Views: 543 💬 Answers: 1 📅 Created: 2025-06-10

kafka avro serialization schema-registry Java

I'm testing a new approach and I'm having trouble with I recently switched to I'm stuck on something that should probably be simple..... I'm currently developing a Java application using Kafka for messaging, and I'm running into issues with message serialization using Avro and a schema registry. My application runs on Java 17 and I'm using the Confluent Kafka library to produce messages. I've defined my Avro schema as follows: ```json { "type": "record", "name": "User", "fields": [ {"name": "id", "type": "int"}, {"name": "name", "type": "string"}, {"name": "email", "type": "string"} ] } ``` In my producer code, I'm trying to serialize an instance of this schema before sending it to Kafka: ```java import org.apache.avro.specific.SpecificRecordBase; import org.apache.avro.specific.SpecificData; import org.apache.kafka.clients.producer.KafkaProducer; import org.apache.kafka.clients.producer.ProducerRecord; import org.apache.kafka.common.serialization.Serializer; import io.confluent.kafka.serializers.KafkaAvroSerializer; KafkaProducer<String, User> producer = new KafkaProducer<>(properties); User user = new User(1, "Jane Doe", "jane.doe@example.com"); ProducerRecord<String, User> record = new ProducerRecord<>("users-topic", user.getId().toString(), user); producer.send(record); ``` However, I keep working with the following behavior when I try to produce a message: ``` org.apache.kafka.common.errors.SerializationException: need to serialize value of type: User ``` I've checked that the dependencies are correctly included in my `pom.xml`: ```xml <dependency> <groupId>io.confluent</groupId> <artifactId>kafka-avro-serializer</artifactId> <version>6.2.1</version> </dependency> ``` I've also ensured that the schema registry is up and running, and I'm configuring the producer properties like this: ```java properties.put("key.serializer", "org.apache.kafka.common.serialization.StringSerializer"); properties.put("value.serializer", "io.confluent.kafka.serializers.KafkaAvroSerializer"); properties.put("schema.registry.url", "http://localhost:8081"); ``` Despite all this, I need to seem to get past the serialization behavior. I've attempted to check the Avro schema compatibility in the schema registry, and it appears to be valid. I also tried to explicitly set a `Serializer<User>` for the value, but nothing seems to work. Does anyone have any idea what might be going wrong or if there's something I'm missing? This is part of a larger service I'm building. How would you solve this? This is for a CLI tool running on macOS. I'd be grateful for any help. I'm working in a Windows 10 environment. Thanks for any help you can provide! Any ideas what could be causing this?