How to make GitHub's Immutables work in IntelliJ + Gradle

Vasiliy :

I use GitHub's Immutables library for Android development, and now I want to give it a try on the backend side as well.

In Android, all I need to to in order to use the library is this:

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])

    // immutable entities generation
    provided "org.immutables:value:2.5.5" // for annotations
    provided "org.immutables:builder:2.5.5" // for annotations
    provided "org.immutables:gson:2.5.5" // for annotations

    ... other dependencies
}

When I attempt to copy the above dependencies into build.gradle of my Java project, I get this error:

Error:(24, 0) Gradle DSL method not found: 'provided()'

I tried to replace provided with compileOnly and compile, but then the implementations of the interfaces annotated with @Value.Immutable are not generated.

How do I make it work?

Vasiliy :

Found the answer. Sharing in case it will be helpful to anyone (or myself in the future).

First of all, I had to enable annotation processing in IntelliJ as described here (though the option is now located in Settings > Build, Execution, Deployment > Compiler > Annotation Processors).

After that the following code started actually generating the implementation:

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])

    // immutable entities generation
    compile "org.immutables:value:2.5.5" // for annotations
    compile "org.immutables:builder:2.5.5" // for annotations
    compile "org.immutables:gson:2.5.5" // for annotations

    ... other dependencies
}

However, I still couldn't automatically import the implementation into source files.

In order to do allow the discovery of the generated classes, I had to right-click on the generated folder in the main package and then Mark Directory As > Generated Sources Root.