Dagger2Retrofit2Final.java

@Module
public class SampleModule {
  private static final int CONNECT_TIMEOUT = 15;
  private static final int WRITE_TIMEOUT = 15;
  private static final int READ_TIMEOUT = 15;
  private static final String baseUrl; // your base url;  
  
  @Provides
  @Singleton
  Cache provideOkHttpCache(Application application) {
    final int cacheSize = 10 * 1024 * 1024; // 10MB
    return new Cache(application.getCacheDir(), cacheSize);
  }

  @Provides
  @Singleton
  Gson provideGson() {
    return new GsonBuilder()
    .registerTypeAdapterFactory(AutoValueGsonFactory.create())
    .create();
  }

  @Provides
  @Singleton
  OkHttpClient provideOkHttpClient(Cache cache, Interceptor interceptor) {
    return new OkHttpClient.Builder()
            .cache(cache)
            .connectTimeout(CONNECT_TIMEOUT, TimeUnit.SECONDS)
            .writeTimeout(WRITE_TIMEOUT, TimeUnit.SECONDS)
            .readTimeout(READ_TIMEOUT, TimeUnit.SECONDS)
            .addInterceptor(interceptor)
            .build();
  }

  @Provides
  @Singleton
  Retrofit provideRetrofit(Gson gson, OkHttpClient okHttpClient) {
    return new Retrofit.Builder()
    .addConverterFactory(GsonConverterFactory.create(gson))
    .baseUrl(baseUrl)
    .client(okHttpClient)
    .build();
  }
  
  @Provides
  @Singleton
  Interceptor provideInterceptor(AccountPreferences prefs) {
    return chain -> {
        if (StringUtil.isNotEmpty(prefs.getToken())) {
            final String bearer = "BEARER " + prefs.getToken();
            final Request.Builder builder = chain.request().newBuilder()
                    .header("Authorization", bearer)
                    .header("Accept", "application/json");

            return chain.proceed(builder.build());
        } else {
            return chain.proceed(chain.request());
        }
    };
  }
}