lombok fails when compile with Gradle 4.5 in Android Studio 3.1.2 - android-studio

Question

I want to use lombok in my Android Studio project.
My current build.gradle project file looks like this:
buildscript {
repositories {
google()
jcenter()
}
dependencies {
classpath 'com.android.tools.build:gradle:3.1.2'
}
}
allprojects {
repositories {
google()
jcenter()
}
}
task clean(type: Delete) {
delete rootProject.buildDir
}
And my app build.gradle file looks like this:
apply plugin: 'com.android.application'
android {
compileSdkVersion 26
defaultConfig {
applicationId "app.getter.android"
minSdkVersion 16
targetSdkVersion 26
versionCode 1
versionName "1.0"
testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
customDebugType {
debuggable true
}
}
}
dependencies {
compileOnly 'org.projectlombok:lombok:1.16.20'
annotationProcessor 'org.projectlombok:lombok:1.16.20'
implementation fileTree(dir: 'libs', include: ['*.jar'])
implementation 'com.android.support:appcompat-v7:26.1.0'
implementation 'com.android.support:design:26.1.0'
testImplementation 'junit:junit:4.12'
androidTestImplementation 'com.android.support.test:runner:1.0.1'
androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.1'
}
I've already installed Lombok Plugin in my Android Studio 3.1.2 and all seems correct. All the lombok tools are available tu use it. The content assist shows all lombok dependencies and there isn't compilation errors in my workspace. However when I try to run a test, Gradle compiles my code and it can't find the lombok generated code like getters/setters or val variables are not transformed to my Java type so it seems that annotationProcessor is not invoked before the compilation or the generated code by the annotationProcessor isn't in the classpath when gradle makes the compilation.
I've tried to use gradle-lombok-plugin but nothing works for me. What I'm doing wrong?