title: Android app with Retrofit2 Crashes without error messages
body: <p>I'm developing an android application which needs to consume rest apis deployed, for now, on an heroku instance...since i got crashes anytime i try to integrate retrofit as http client I've done the following:</p>
  
  <p>Added retrofit2 as dependendcy (didn't choose the latest version in order to avoid potential maturity problems)</p>
  
  <pre><code>compile 'com.squareup.retrofit2:retrofit:2.0.0'
  compile 'com.squareup.retrofit2:converter-gson:2.0.0'
  
  compile 'com.google.code.gson:gson:2.6.2'
  </code></pre>
  
  <p>I coded an example android app, just to check if something has been done wrong in my original app, using <a href="http://httpbin.org/ip" rel="nofollow noreferrer">http://httpbin.org/ip</a></p>
  
  <pre><code>public interface HttpBinService
  {
  public static class Response
  {
      private String origin;
  
      public Response(String origin) {
          this.origin = origin;
      }
  
      public String getOrigin() {
          return origin;
      }
  
      public void setOrigin(String origin) {
          this.origin = origin;
      }
  }
  
  @GET("ip")
  public Call&lt;Response&gt; getIp ();
  }
  </code></pre>
  
  <p>And the main activity</p>
  
  <pre><code>public class MainActivity extends AppCompatActivity {
  
  @Override
  protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
  
      // Retrofit setup
      Retrofit retrofit = new Retrofit.Builder()
              .baseUrl("http://httpbin.org")
              .addConverterFactory(GsonConverterFactory.create())
              .build();
  
      // Service setup
      HttpBinService service = retrofit.create(HttpBinService.class);
      try {
          Call&lt;HttpBinService.Response&gt; call = service.getIp();
  
          Response&lt;HttpBinService.Response&gt; res = call.execute();
  
          if (res.isSuccessful()){
              Log.i("PROVARETROFIT", "OK");
  
              ((TextView)findViewById(R.id.testo)).setText(res.body().getOrigin());
          }
      } catch (IOException e) {
          e.printStackTrace();
      }
  }
  </code></pre>
  
  <p>}</p>
  
  <p>I did not forget to ask for internet permissions in my manifest</p>
  
  <pre><code>&lt;manifest xmlns:android="http://schemas.android.com/apk/res/android"
  package="it.spich.provaretrofit"&gt;
  
  &lt;uses-permission android:name="android.permission.INTERNET"/&gt;
  &lt;application
      android:allowBackup="true"
      android:icon="@mipmap/ic_launcher"
      android:label="@string/app_name"
      android:supportsRtl="true"
      android:theme="@style/AppTheme"&gt;
      &lt;activity android:name=".MainActivity"&gt;
          &lt;intent-filter&gt;
              &lt;action android:name="android.intent.action.MAIN" /&gt;
  
              &lt;category android:name="android.intent.category.LAUNCHER" /&gt;
          &lt;/intent-filter&gt;
      &lt;/activity&gt;
  &lt;/application&gt;
  </code></pre>
  
  <p></p>
  
  <p>But all i got is that application closes unexpectedly. If t execute it in debug, it executes correctly all steps until call execution. LogCat appears to not say anything useful</p>
  
  <pre><code>04-15 09:48:08.281 6491-6491/? I/art: Late-enabling -Xcheck:jni
  04-15 09:48:08.367 6491-6491/? W/System: ClassLoader referenced unknown path: /data/app/it.spich.provaretrofit-1/lib/arm64
  04-15 09:48:08.387 6491-6491/it.spich.provaretrofit I/HwCust: Constructor found for class android.app.HwCustHwWallpaperManagerImpl
  04-15 09:48:08.577 6491-6491/? I/Process: Sending signal. PID: 6491 SIG: 9
  </code></pre>
  
  <p>Has someone idea of what is happening there?</p>