Java producer client in Kafka - Mini Project: Build & Apply

Java Producer Client

📖 Scenario: You are building a simple Java program that sends messages to a Kafka topic. Kafka is like a post office where your program can send letters (messages) to a specific mailbox (topic).In this project, you will create a Java Kafka producer client that sends messages to a topic named test-topic.

🎯 Goal: Build a Java Kafka producer client that sends three messages to the test-topic Kafka topic.

📋 What You'll Learn

Create a Java Properties object with Kafka producer configuration

Create a Kafka Producer<String, String> object

Send three messages with keys and values to the test-topic

Close the producer after sending messages

💡 Why This Matters

🌍 Real World

Kafka producers are used in real applications to send data streams like logs, user activity, or sensor data to Kafka topics for processing.

💼 Career

Understanding how to build Kafka producer clients in Java is essential for backend developers working with real-time data pipelines and event-driven architectures.

1

Create Kafka producer configuration

Create a Properties object called props and set these exact properties:
bootstrap.servers to "localhost:9092",
key.serializer to "org.apache.kafka.common.serialization.StringSerializer",
and value.serializer to "org.apache.kafka.common.serialization.StringSerializer".

Kafka

import java.util.Properties;

// Your code here

Need a hint?

Use props.put(key, value) to set each configuration property.

2

Create Kafka producer client

Create a Kafka Producer<String, String> object called producer using the props configuration.

Kafka

import org.apache.kafka.clients.producer.KafkaProducer;
import org.apache.kafka.clients.producer.Producer;

Properties props = new Properties();
props.put("bootstrap.servers", "localhost:9092");
props.put("key.serializer", "org.apache.kafka.common.serialization.StringSerializer");
props.put("value.serializer", "org.apache.kafka.common.serialization.StringSerializer");

// Your code here

Need a hint?

Use new KafkaProducer<>(props) to create the producer.

3

Send messages to Kafka topic

Use the producer.send() method to send these three messages to the test-topic topic:
1. Key: "key1", Value: "Hello Kafka 1"
2. Key: "key2", Value: "Hello Kafka 2"
3. Key: "key3", Value: "Hello Kafka 3"
Use new ProducerRecord<>(topic, key, value) to create each message.

Kafka

import org.apache.kafka.clients.producer.KafkaProducer;
import org.apache.kafka.clients.producer.Producer;
import org.apache.kafka.clients.producer.ProducerRecord;
import java.util.Properties;

Properties props = new Properties();
props.put("bootstrap.servers", "localhost:9092");
props.put("key.serializer", "org.apache.kafka.common.serialization.StringSerializer");
props.put("value.serializer", "org.apache.kafka.common.serialization.StringSerializer");

Producer producer = new KafkaProducer(props);

// Your code here

Need a hint?

Call producer.send() three times with the correct ProducerRecord arguments.

4

Close the Kafka producer and print confirmation

Close the producer using producer.close().
Then print exactly "Messages sent successfully" using System.out.println().

Kafka

import org.apache.kafka.clients.producer.KafkaProducer;
import org.apache.kafka.clients.producer.Producer;
import org.apache.kafka.clients.producer.ProducerRecord;
import java.util.Properties;

Properties props = new Properties();
props.put("bootstrap.servers", "localhost:9092");
props.put("key.serializer", "org.apache.kafka.common.serialization.StringSerializer");
props.put("value.serializer", "org.apache.kafka.common.serialization.StringSerializer");

Producer producer = new KafkaProducer(props);

producer.send(new ProducerRecord("test-topic", "key1", "Hello Kafka 1"));
producer.send(new ProducerRecord("test-topic", "key2", "Hello Kafka 2"));
producer.send(new ProducerRecord("test-topic", "key3", "Hello Kafka 3"));

// Your code here

Need a hint?

Call producer.close() to release resources.
Use System.out.println("Messages sent successfully") to print the confirmation.