Original kapt is deprecated

Source: Annotation Processing with Kotlin

Source Link 1: https://kotlinlang.org/docs/reference/kapt.html

Source Link 2:https://github.com/uber/NullAway/issues/75

Kotlin plugin doesn't pick up annotationProcessor dependencies, So we have to use kapt dependencies with kotlin-kapt.

Use the latest version of Kotlin annotation processor put this line at top of your module's level build.gradle file

apply plugin: 'kotlin-kapt'

Like

apply plugin: 'kotlin-android'
apply plugin: 'kotlin-android-extensions'
apply plugin: 'kotlin-kapt'  // add this line

android {
    compileSdkVersion 27
    defaultConfig {
      ........
    }
}

Don't forget to update the version when you use different build plugin version.

Add kotlin-kapt plugin in your app-level build.gradle file.

Update your gradle like this:

apply plugin: 'com.android.application'
apply plugin: 'kotlin-android'
apply plugin: 'kotlin-android-extensions'
apply plugin: 'kotlin-kapt'  // add this line

android {
    compileSdkVersion 27
    defaultConfig {
      ........
    }
}

I was getting this error after adding apply plugin: 'realm-android' so the problem was the order of statements. This order worked for me

apply plugin: 'realm-android'
apply plugin: 'kotlin-android'
apply plugin: 'kotlin-android-extensions'