How Amazon Q Developer transforms code for Java language upgrades

To transform your code, Amazon Q Developer generates a transformation plan that it uses to upgrade the code language version of your project. After transforming your code, it provides a transformation summary and a file diff for you to review changes before accepting them. Since Amazon Q Developer makes the minimal changes necessary to make your upgraded code compatible with the target JDK, an additional transformation is required to upgrade your project's libraries and dependencies. The following sections provide more details on how Amazon Q performs the transformation.

Building your code and creating a transformation plan

To begin transforming your code, Amazon Q builds your project locally and generates a build artifact that contains your source code, project dependencies, and build logs.

After generating the build artifact, Amazon Q builds your code in a secure build environment and creates a transformation plan, which is customized to the project or module you’re upgrading. The transformation plan outlines the specific changes Amazon Q will attempt to make, including new dependency versions, major code changes, and suggested replacements for deprecated code. These changes are based on the preliminary build of your code, and might change during the transformation.

Transforming your code

To transform your code, Amazon Q attempts to upgrade your code to the target Java version based on the proposed changes in the transformation plan. As it makes changes, it re-builds and runs existing unit tests in your source code to iteratively fix any encountered errors. The JDK upgrade can be made from the following source code version to the target version:

Amazon Q Developer makes the minimal changes necessary to make your code compatible with the target Java version. After successfully upgrading to Java 17 or 21, an additional transformation is required to upgrade your project's libraries and dependencies. Choose the same source code version and target code version (for example, 17 to 17).

Amazon Q attempts to make the following changes when upgrading your code:

Reviewing the transformation summary and accepting changes

After the transformation is complete, Amazon Q provides a transformation summary with details about the changes it made, including the status of the final build which indicates whether your entire project was upgraded. You can also view a build log summary to understand any issues that prevented Amazon Q from building your code in the upgraded version.

The transformation summary additionally includes the differences between the changes proposed in the transformation plan and the changes Amazon Q ultimately made to upgrade your code, and any additional changes that weren’t in the original plan.

After you review the transformation summary, you can view the changes Amazon Q is proposing in a file diff view. Any code changes Amazon Q suggests will not affect your current project files until you accept the changes. The transformed code is available up to 30 days after the transformation completes.

Completing partially successful transformations

Depending on the complexity and specifics of your codebase, there might be instances where the transformation is partially successful. This means that Amazon Q was able to transform only certain files or areas of code in your project. In this case, you have to manually update the remaining code for your project to be buildable in the updated language version.

To help transform the rest of your code, you can use Amazon Q chat in the IDE. You can ask Amazon Q to review the partially updated files and provide new code to address issues, such as compilation errors. You can also use features like /dev and @workspace to include more of your project as context and get suggestions for multiple files at a time.