Dagger example with App & Net Module

App.java

public class App extends Application {
    private static final String TAG = "App";
    private NetComponent mNetComponent;

    @Override
    public void onCreate() {
        super.onCreate();
        mNetComponent = DaggerNetComponent.builder()
                .appModule(new AppModule(this)) // This also corresponds to the name of your module: %component_name%Module
                .netModule(new NetModule(UrlHelper.getBaseUrl()))
                .build();


    }

    public NetComponent getNetComponent() {
        return mNetComponent;
    }

}

AppModule.java

@Module
class AppModule {

    private Application mApplication;

    AppModule(Application application) {
        mApplication = application;
    }

    @Provides
    @Singleton
    Application providesApplication() {
        return mApplication;
    }

    @Provides
    @Singleton
    Realm providesRealm(Application application) {
        RealmConfiguration realmConfig = new RealmConfiguration.Builder(application)
                .deleteRealmIfMigrationNeeded()
                .build();
        Realm.setDefaultConfiguration(realmConfig);
        return Realm.getDefaultInstance();

    }

}

NetComponent.java

@Singleton
@Component(modules = {AppModule.class, NetModule.class})
public interface NetComponent {
    void inject(LoginActivity activity);

}

NetModule.java

@Module
class NetModule {

    private String mBaseUrl;

    // Constructor needs one parameter to instantiate.
    NetModule(String baseUrl) {
        this.mBaseUrl = baseUrl;
    }

    @Provides
    @Singleton
    SharedPreferences providesSharedPreferences(Application application) {
        return PreferenceManager.getDefaultSharedPreferences(application);
    }

    @Provides
    @Singleton
    Session providesSession(Application application) {
        return new Session(application);
    }

    @Provides
    @Singleton
    Gson provideGson() {
        GsonBuilder gsonBuilder = new GsonBuilder();
        gsonBuilder.setFieldNamingPolicy(FieldNamingPolicy.LOWER_CASE_WITH_UNDERSCORES);
        return gsonBuilder.create();
    }

    @Provides
    @Singleton
    Retrofit providesRetrofit(OkHttpClient okHttpClient) {
        // TODO: Use your own attributes to track content views in your app

        return new Retrofit.Builder()
                .baseUrl(mBaseUrl)
                .addConverterFactory(GsonConverterFactory.create())
                .client(okHttpClient)
                .addCallAdapterFactory(RxJavaCallAdapterFactory.create())
                .build();
    }

    @Provides
    @Singleton
    OkHttpClient provideOkHttpClient() {
        HttpLoggingInterceptor logging = new HttpLoggingInterceptor();
        logging.setLevel(HttpLoggingInterceptor.Level.BODY);

        Interceptor interceptor = new Interceptor() {
            @Override
            public okhttp3.Response intercept(Chain chain) throws IOException {
                Request newRequest = chain.request()
                        .newBuilder()
                        .addHeader("User-Agent", "Android APP").build();
                return chain.proceed(newRequest);
            }
        };
        return new OkHttpClient.Builder()
                .addInterceptor(logging)
                .addInterceptor(interceptor)
                .build();
    }

}