Deploying a Java Spring Boot Application to Heroku

Deploying a Java application to the cloud can often feel complex, but Platform as a Service (PaaS) providers like Heroku make the deployment workflow straightforward and efficient.

In this guide, we will walk through the steps required to take a Spring Boot application (managed with Maven) and deploy it live to the cloud using the Heroku CLI and Git.

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Step 1: Create a Heroku Account

The first step is setting up an account on the official Heroku platform. The dashboard will allow you to manage application dynos, databases, and environment variables.

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Step 2: Install the Heroku CLI

To interact with cloud services directly from your local terminal, install the Heroku CLI.

Once installed, authenticate your terminal session:

heroku login

This command opens a browser window to complete the login process. You can verify that your SSH keys are correctly linked by running:

heroku keys

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Step 3: Prepare the Spring Boot Application

If you don’t have a Spring Boot project ready, generate one using Spring Initializr:

1. Choose a Maven Project with Java.
2. Add the Spring Web dependency.
3. Download and extract the project archetype onto your machine.

Ensure your pom.xml contains the Spring Boot Maven build plugin required to generate an executable .jar:

<build>
    <plugins>
        <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
        </plugin>
    </plugins>
</build>

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Step 4: Initialize the Git Repository

Heroku handles application deployments by integrating seamlessly with Git. Initialize a local Git repository within your project folder:

# Initialize repository and create initial commit
git init
git add .
git commit -m "Initial Spring Boot commit"

It is also recommended to host your source code on a remote provider like GitHub.

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Step 5: Create the Heroku Application

From the root directory of your project, create a new Heroku cloud application:

heroku create

Heroku will provision a cloud instance with a randomly generated name and automatically attach a remote Git endpoint named heroku to your local repository.

To customize the app name, rename it at any time using:

heroku apps:rename my-custom-app-name

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Step 6: Deploy the Application

To trigger the build build process and deploy your application, push your code to the Heroku remote branch:

git push heroku main

(Note: if your local primary branch is named master, use git push heroku master).

During execution, Heroku will automatically detect a Java/Maven project, resolve dependencies defined in pom.xml, compile the binary, and boot the application.

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Step 7: Execution, Logging, and Monitoring

When the deployment finishes, launch the application in your default browser:

heroku open

Useful CLI Commands for Management:

• Stream live application logs:

  heroku logs --tail

• Restart dyno instances:

  heroku restart

Whenever you update your code, commit your changes locally and run git push heroku main to deploy the latest version to the cloud.