Micronaut, a popular Java and Kotlin microservices framework, provides robust support for annotation processing. Kotlin Annotation Processing Tool (KAPT) is an essential part of this ecosystem, allowing you to generate code based on annotations. In this blog, we’ll explore how to enable KAPT in a Micronaut project and leverage its power to simplify code generation and streamline development.

What is KAPT?

KAPT is a Kotlin-specific annotation processing tool that works similarly to Java’s annotation processing. It allows you to define custom annotations and generate code during compilation based on these annotations. This code generation can be used for various purposes, such as creating builders, implementing dependency injection, or generating configuration files.

Enabling KAPT in Micronaut

Enabling KAPT in your Micronaut project is straightforward:

1. Add Dependencies:

In your project’s build.gradle (or build.gradle.kts for Kotlin projects), apply the KAPT plugin.

apply plugin: 'kotlin-kapt'

2. Use Kapt

Now you can use kapt to import libraries that needs annotation processor support

kapt('io.micronaut.data:micronaut-data-processor:3.9.6')

3. Trobleshooting

One of the general issue that is faced is same class gets included in Jar 2 times which leads to build failure. We can overcome this by declaring duplicate policies

tasks.withType(Jar).all { duplicatesStrategy 'exclude' }

4. Build Your Project:

Build your Micronaut project, and KAPT will automatically process your annotations, generating code or performing other tasks as defined in annotation processor.

Enabling KAPT in Micronaut opens up new possibilities for code generation and automation. You can use it to simplify repetitive tasks, enhance code readability, and create powerful abstractions. By following the steps outlined in this blog, you can harness the full potential of KAPT within your Micronaut projects, making your development process more efficient and maintainable.