If you’re a developer working with Spring Boot, you’re probably aware of the rapid evolution of this powerful framework. With each new version, Spring Boot brings improvements, new features, and bug fixes. In this blog post, i will guide you through upgrading your Spring Boot service from version 2.7.x to the latest 3.1.x using the OpenRewrite recipe. I’ll cover all available options and provide step-by-step instructions, including Maven commands.

Major Changes in Spring Boot 3.x

Before we dive into the upgrade process, let’s briefly discuss some of the major changes introduced in Spring Boot 3.x compared to 2.7.x. Understanding these changes will help you better navigate the upgrade process.

1. Java 17 Support: Spring Boot 3.x fully embraces Java 17, providing improved performance, security, and new language features. Make sure your project is compatible with Java 17 before upgrading.
2. Modularization: Spring Boot 3.x encourages a more modular approach to building applications. You’ll notice improved support for modular JARs and enhanced modularity features.
3. Project Loom (lightweight virtual threads): Spring Boot 3.x takes advantage of Project Loom’s lightweight concurrency model, which can lead to significant performance improvements in certain scenarios.
4. Updated Dependencies: Many of the core dependencies in Spring Boot have been updated to their latest versions, providing bug fixes and new features.

Now that you’re familiar with some of the key changes, let’s proceed with the upgrade process.

Upgrading with OpenRewrite Recipe

Upgrading your Spring Boot project using OpenRewrite involves a series of steps. OpenRewrite provides various usage options, including Gradle, Gradle init script, Maven POM, and Maven command line. In this guide, I will focus on the Maven POM option for applying the Spring Boot upgrade recipe. This approach provides a structured and easily replicable way to upgrade your project, ensuring a smooth transition to Spring Boot 3.1.x.

Configure Maven Plugin in Your `pom.xml`

First, you’ll need to configure the OpenRewrite Maven plugin in your project’s pom.xml file. Add the following configuration within the <plugins> section:

Replace versions with the latest version of the OpenRewrite Maven plugin and recipe available.

Dry Run the OpenRewrite Recipe

Before making any actual changes to your project, it’s a good practice to perform a dry run to see if the OpenRewrite recipe can be applied successfully. Run the following Maven command with the dryRun option. Below you can find sample console logs when you run following command:

mvn rewrite:dryRun

Apply the OpenRewrite Recipe

Once you’ve successfully completed the dry run and verified that the recipe can be applied without issues, it’s time to run the actual command to upgrade your project. Execute the following Maven command:

mvn rewrite:run

This command will apply the necessary changes to your project based on the OpenRewrite recipe. Below you can find sample console logs

Review Changes to pom.xml and Other Files

After running the OpenRewrite recipe, your project’s pom.xml file and potentially other configuration files might have been updated. Review these changes to ensure they align with your project’s requirements and dependencies.

Make any additional adjustments to your codebase or configuration files as needed to accommodate the changes introduced by the upgrade.

Congratulations!!! By following these steps, you’ll have successfully upgraded your Spring Boot service from version 2.7.x to 3.1.x using the OpenRewrite recipe, all while carefully reviewing and testing each phase of the upgrade process.

Final Thoughts

Upgrading a Spring Boot project can be a complex process, but with the help of OpenRewrite, it becomes more manageable. Remember to follow best practices, thoroughly test your application, and consult the official Spring Boot documentation and release notes for specific version details. Enjoy the benefits of Spring Boot 3.1.x in your upgraded project!