Auto code formatting Java/Kotlin

Context:

We are working on a Java project. Our typical day has a lot of code review tasks that need to be done. Before pushing our source code, we usually do the code format by the local tool such as Eclipse, or IntelliJ. But sometimes, the developer forgets to format the code. And the result of PR (pull request) contains the mess from the formatting.

Solution:

We add a required step for every code push which is spotlessCheck, it prevents the code push if the local code is invalid format.

Spotless with Gradle

plugins {
    id("com.diffplug.spotless") version "6.11.0"
}

spotless {
    kotlin {
        ktfmt().googleStyle()
    }
}

Check the version at https://mvnrepository.com/artifact/com.diffplug.spotless/spotless-plugin-gradle

Testing

gradlew build

Execution failed for task ':backend:spotlessKotlinCheck'.
> The following files had format violations:
      src\main\kotlin\io\nettable\config\MongoConfiguration.kt
          @@ -9,21 +9,19 @@

Fixing your code

gradlew spotlessApply

Now local code is ready to push in beautiful format (google style)