public class MainActivity extends AppCompatActivity {
  Retrofit retrofit;
  
  @Override
  protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
      /*
      Rest
      */
      initNetwork();
  }
  
  private void initNetwork() {
    retrofit = new Retrofit.Builder()
                .baseUrl(Constants.API_BASE_URL)
                .addConverterFactory(GsonConverterFactory.create())
                .client(SelfSigningClientBuilder.createClient(this))
                .build();
                
    /*
     *Do the rest of Retrofit work
     */
  }
}