Learn how to create a Java project using Gradle that can interact with Kafka cluster. Before developing Kafka producers and consumers in Java, we’ll have to set up a simple Kafka Java project that includes common dependencies that we’ll need, namely:
  • Kafka dependencies
  • Logging dependencies
Follow these steps to create a Java project with the above dependencies.

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Creating a Kafka Gradle project with build.gradle and setting up dependencies

In IntelliJ IDEA, create a new Java Gradle project (File > New > Project) Screenshot showing how to create a new project file for your Kafka Gradle Java Project in IntelliJ Then add your Gradle project attributes Intellij screenshot showing how to add attributes to your Kafka Gradle project in Java. The build tool Gradle contains a **build.gradle** file. The build.gradle is a default Gradle file that carries all the information regarding the Group and Version values . The user needs to define all the necessary project dependencies in the build.gradle file. Go to the build.gradle file. Screenshot showing how to define dependencies for your Kafka project in Gradle. Define the Kafka Dependencies in the dependencies { ... } block. Add a dependency for Kafka client and logging dependencies as shown below 
dependencies {
    // https://mvnrepository.com/artifact/org.apache.kafka/kafka-clients
    implementation 'org.apache.kafka:kafka-clients:2.8.1'

    // https://mvnrepository.com/artifact/org.slf4j/slf4j-api
    implementation 'org.slf4j:slf4j-api:1.7.32'

    // https://mvnrepository.com/artifact/org.slf4j/slf4j-simple
    implementation 'org.slf4j:slf4j-simple:1.7.32'
    
    testImplementation 'org.junit.jupiter:junit-jupiter-api:5.6.0'
    testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine'
}
Load the Gradle changes with the menu from the right hand side to import the dependencies Screenshot showing how to load the Gradle changes to your Kafka project using the right hand menu. Now, we have set all the required dependencies. Let’s try the Simple Hello World example.

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Creating your first class

Create a java package say, io.conduktor.demos.kafka.HelloWorld Screenshot showing the New Java Class dialog for your Kafka Gradle project While creating the java package, follow the package naming conventions. Finally, create the sample application program as shown below. 
package io.conduktor.demos.kafka;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class HelloWorld {
    private static final Logger log = LoggerFactory.getLogger(HelloWorld.class);

    public static void main(String[] args) {
        log.info("Hello World");
    }
}
Run the application (the play green button on line 9 in the screenshot below) and verify that it runs and prints the message, and exits with code 0. This means that your Java application has run successfully. Expand the ‘External Libraries’ on the Project panel and verify that it displays the dependencies that we added for the project in build.gradle file Screenshot showing successful setup of your Kafka Gradle project in Java. We have created a sample Java project that includes all the needed dependencies. This will form the basis for creating Java producers and consumers next.