Lombok in Android Studio 2.2 with Jack Compiler

README.md

Steps

1. Install the Lombok plugin via Android Studio -> Preferences -> Plugins (Search repositories).
2. Enable Annotation Processing. With the project open go to: File -> Other Settings -> Default Settings Build, Executio... -> Compiler -> Annotation Processors
3. Finally to be sure click File -> Invalidate Cache and Restart Android Studio

What does Lombok do?

• Remove tonnes of boilerplate around generating value classes, getter/setters, builders, null value checks, all kinds of good stuff. See https://projectlombok.org/features/index.html

In this example I just use the @Data annotation to generate getters/setters, toString() and hashCode() - in reality you may want to use the @Getter annotation and others to exact a more fine grained control (or to generate immutable classes with @Value).

app_build.gradle

buildscript {
    repositories {
        mavenCentral()
    }
}

apply plugin: 'com.android.application'

android {
    compileSdkVersion 25
    buildToolsVersion "24.0.2"
    defaultConfig {
        applicationId "com.myapp"
        minSdkVersion 19
        targetSdkVersion 25
        versionCode 1
        versionName "0.1"
        jackOptions {
            enabled true
        }
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
    productFlavors {
        dev {
            // dev utilizes minSDKVersion = 21 to allow the Android gradle plugin
            // to pre-dex each module and produce an APK that can be tested on
            // Android Lollipop without time consuming dex merging processes.
            minSdkVersion 21
            applicationIdSuffix ".dev"
        }
        staging {
            // staging utilizes minSDKVersion = 21 to allow the Android gradle plugin
            // to pre-dex each module and produce an APK that can be tested on
            // Android Lollipop without time consuming dex merging processes.
            minSdkVersion 21
            applicationIdSuffix ".staging"
        }
        production {
            minSdkVersion 15
        }
    }

    packagingOptions {
        exclude 'LICENSE.txt'
    }
}

dependencies {
    compile fileTree(include: ['*.jar'], dir: 'libs')
    
    // Testing framework
    testCompile 'junit:junit:4.12'
    androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
        exclude group: 'com.android.support', module: 'support-annotations'
    })
    testCompile 'org.mockito:mockito-core:2.2.8'
    androidTestCompile 'org.mockito:mockito-core:2.2.8'
    
    // Dagger dependency injection library
    provided 'javax.annotation:jsr250-api:1.0'
    compile 'com.google.dagger:dagger:2.7'
    annotationProcessor "com.google.dagger:dagger-compiler:2.7"
    
    // Support libraries
    compile 'com.android.support:appcompat-v7:25.0.0'
    compile 'com.android.support.constraint:constraint-layout:1.0.0-alpha4'
    
    // Retrofit and OKHTTP
    compile 'com.squareup.retrofit2:retrofit:2.1.0'
    compile 'com.squareup.retrofit2:converter-gson:2.1.0'
    compile 'com.squareup.retrofit2:converter-scalars:2.1.0'
    compile 'com.squareup.retrofit2:adapter-rxjava:2.1.0'
    compile 'com.squareup.okhttp3:okhttp:3.3.0'
    compile 'com.squareup.okhttp3:logging-interceptor:3.3.0'
    
    // RxJava
    compile 'io.reactivex:rxjava:1.0'
    
    // Jodatime
    compile 'joda-time:joda-time:2.9.3'
    
    // Lombok
    provided 'org.projectlombok:lombok:1.16.10'
}

project_build.gradle

// Top-level build file where you can add configuration options common to all sub-projects/modules.

buildscript {
    repositories {
        jcenter()
        mavenCentral()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:2.2.2'

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

allprojects {
    repositories {
        jcenter()
    }
}

task clean(type: Delete) {
    delete rootProject.buildDir
}

SampleBaseModel.java

package com.myapp;

import com.google.gson.annotations.SerializedName;

import org.joda.time.DateTime;

import lombok.Data;


/**
 * Base for all entities the API returns
 */
@Data
public abstract class BaseModel {
    @SerializedName("id")
    String id = null;

    @SerializedName("createdAt")
    DateTime createdAt = null;

    @SerializedName("updatedAt")
    DateTime updatedAt = null;

    @SerializedName("modelType")
    String modelType = null;
}

SampleModel.java

package com.myapp;

import com.google.gson.annotations.SerializedName;

import lombok.Data;
import lombok.EqualsAndHashCode;

/**
 * Some child model class
 */
@Data
@EqualsAndHashCode(callSuper=true)
public class SampleModel extends BaseModel {

  @SerializedName("aField")
  private String aField = null;
}

Usage.java

package com.myapp.test;

import com.myapp.api.model.SampleModel;
import com.myapp.api.model.BaseModel;

import org.joda.time.DateTime;
import org.junit.Test;

import static junit.framework.Assert.assertEquals;

/**
 * Tests that Lombok is correctly generating our model class methods
 */
public class LombokDomainModelTest {
    @Test
    public void sampleModelHasBaseModelFields() {
        DateTime now = DateTime.now();

        SampleModel model = new SampleModel();
        model.setCreatedAt(now);

        assertEquals(now, model.getCreatedAt());
    }

    @Test
    public void identicalSampleModelsHaveEquality() {
        DateTime now = DateTime.now();

        SampleModel model = new SampleModel();
        model.setCreatedAt(now);

        SampleModel model2 = new SampleModel();
        model2.setCreatedAt(now);

        assertEquals(model, model2);
    }
}

Same for @AllArgsConstructor