How to call annotation processor from Gradle plugin

After a long search and a lot of trying and failing, I finally found a solution to my problem. Here is my task configuration.

Basically, we have to provide the classpath of the annotation processor as project configuration. In my case, I added this block to my project's build.gradle

allprojects {
    configurations {
        myProcessor //pick any name!!!
    }
}

Then as a dependency in the app build.gradle

dependencies {
    myProcessor "PATH_TO_MY_PROCESSOR_JAR" //or maven dependency if it's uploaded to maven central
}

tasks.register(
"myTaskName",
JavaCompile::class.java
) {
    compiler ->
    with(compiler.options) {
        isFork = true
        isIncremental = true
    }
    with(compiler) {
        group = shuttle.plugin.ShuttlePlugin.TASK_GROUP
        destinationDir = outputDir
        classpath = variant.getCompileClasspath(null)
        options.annotationProcessorPath = configurations.getByName("myProcessor") //this is the missing piece!!
        source = files(projectDir.resolve("src/main/java")).asFileTree
    }
}

However, this task will only compile Java classes , only not Kotlin . Knowing that my plugin only targets android apps, so I don't have direct access to kotlinCompilegradle default tasks?