Hands-on tutorial: Containerizing a Java application with Jib

18 Sep 2023

Containerization

In this hands-on tutorial, we will explore containerizing a Java application using Jib, a powerful containerization tool that simplifies the container build process. Jib abstracts away the complexity of Dockerfiles and container registries, making it easier for developers to package and distribute their Java applications.

Prerequisites

Before getting started, make sure you have the following prerequisites:

Java Development Kit (JDK) installed
Apache Maven or Gradle build tool installed
Docker installed on your machine

Step 1: Setting up the Java Application

To demonstrate containerization with Jib, let’s create a simple Java application. Create a new directory, navigate inside it, and run the following commands:

# Create a new Java class
mkdir src/main/java/com/example/myapp
echo 'public class App {
    public static void main(String[] args) {
        System.out.println("Hello, Containerized World!");
    }
}' > src/main/java/com/example/myapp/App.java

# Create a Maven project
mvn archetype:generate -DgroupId=com.example.myapp -DartifactId=myapp -DarchetypeArtifactId=maven-archetype-quickstart -DinteractiveMode=false

This will create a new Java class called App inside the com.example.myapp package and initialize a Maven project structure.

Step 2: Adding Jib to the Project

Next, let’s add Jib to our project’s build configuration. Open the pom.xml file in the root of your project and add the following plugin configuration inside the <build> section:

<plugins>
    <!-- ...other plugins... -->

    <plugin>
        <groupId>com.google.cloud.tools</groupId>
        <artifactId>jib-maven-plugin</artifactId>
        <version>3.0.0</version>
        <configuration>
            <to>
                <image>myapp:latest</image>
            </to>
        </configuration>
    </plugin>
</plugins>

This configuration sets the target image name to myapp:latest.

Step 3: Building and Containerizing with Jib

With Jib configured in our project, we can now build and containerize our Java application. Run the following Maven command:

mvn clean package jib:dockerBuild

This command will build the application, create a Docker image, and push it to your local Docker registry. Jib automatically handles all the necessary steps, including building a container image with the application dependencies.

Step 4: Running the Containerized Java Application

To run the containerized Java application, simply execute the following Docker command:

docker run myapp:latest

You should see the output: Hello, Containerized World!.

Congratulations! You have successfully containerized a Java application using Jib. Containerization simplifies deployment and ensures that your applications run consistently across different environments.

Conclusion

Containerization has become an integral part of modern software development. With tools like Jib, containerizing Java applications has become simpler than ever before. By following this hands-on tutorial, you have learned how to containerize a Java application using Jib, enabling you to easily package and distribute your applications with ease.

#Java #Containerization