Kafka integration basics in Spring Boot - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a Kafka topic bean in Spring Boot.

Spring Boot

import org.apache.kafka.clients.admin.NewTopic;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class KafkaTopicConfig {

    @Bean
    public NewTopic [1]() {
        return new NewTopic("my_topic", 1, (short) 1);
    }
}

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AtopicBean

BcreateTopic

CnewTopic

DkafkaTopic

Attempts:

3 left

💡 Hint

Common Mistakes

Using a method name that does not clearly indicate it creates a topic.

Not annotating the method with @Bean.

The method name defining the Kafka topic bean can be any valid method name, but createTopic is a common and clear choice.

2fill in blank

medium

Complete the code to send a message to a Kafka topic using KafkaTemplate.

Spring Boot

import org.springframework.kafka.core.KafkaTemplate;
import org.springframework.stereotype.Service;

@Service
public class ProducerService {

    private final KafkaTemplate<String, String> kafkaTemplate;

    public ProducerService(KafkaTemplate<String, String> kafkaTemplate) {
        this.kafkaTemplate = kafkaTemplate;
    }

    public void sendMessage(String message) {
        kafkaTemplate.[1]("my_topic", message);
    }
}

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Asend

Bpublish

Cproduce

Dwrite

Attempts:

3 left

💡 Hint

Common Mistakes

Using method names that do not exist on KafkaTemplate.

Confusing send with other verbs like publish or write.

The KafkaTemplate class uses the send method to send messages to a Kafka topic.

3fill in blank

hard

Fix the error in the Kafka listener method annotation to listen to the correct topic.

Spring Boot

import org.springframework.kafka.annotation.KafkaListener;
import org.springframework.stereotype.Service;

@Service
public class ConsumerService {

    @KafkaListener(topics = "[1]", groupId = "group_id")
    public void consume(String message) {
        System.out.println("Received message: " + message);
    }
}

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Amy_topic

Btopic1

Cdefault_topic

Dkafka_topic

Attempts:

3 left

💡 Hint

Common Mistakes

Using a different topic name than the producer sends to.

Misspelling the topic name.

The listener must subscribe to the same topic name used when sending messages, which is my_topic.

4fill in blank

hard

Fill both blanks to configure Kafka consumer properties in application.yml.

Spring Boot

spring:
  kafka:
    consumer:
      bootstrap-servers: localhost:9092
      group-id: [1]
      key-deserializer: [2]

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Amy_group

Borg.apache.kafka.common.serialization.StringDeserializer

Corg.apache.kafka.common.serialization.IntegerDeserializer

Ddefault_group

Attempts:

3 left

💡 Hint

Common Mistakes

Using default group id that may conflict with others.

Using wrong deserializer class for string keys.

The group-id should be a custom group name like my_group. The key-deserializer for string keys is org.apache.kafka.common.serialization.StringDeserializer.

5fill in blank

hard

Fill all three blanks to create a Kafka listener method that listens to two topics and uses a specific group id.

Spring Boot

import org.springframework.kafka.annotation.KafkaListener;
import org.springframework.stereotype.Service;

@Service
public class MultiTopicConsumer {

    @KafkaListener(topics = {"[1]", "[2]"}, groupId = "[3]")
    public void listen(String message) {
        System.out.println("Message received: " + message);
    }
}

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AtopicA

BtopicB

Cmulti_group

Ddefault_group

Attempts:

3 left

💡 Hint

Common Mistakes

Using the same topic twice.

Using a default group id that conflicts with others.

The listener subscribes to topicA and topicB with the consumer group multi_group.