title: Java Android FirebaseMessagingService: onMessageReceived not called at all
body: <p>I have a problem with my FirebaseMessagingService java class. When I send a notification from the Firebase console the <code>onMessageReceived</code> function isn't called at all. But I know I successfully sent the notification, here is my code:</p>
  
  <pre><code>package com.nufdev.firelink.other;
  
  import android.app.NotificationManager;
  import android.app.PendingIntent;
  import android.content.Context;
  import android.content.Intent;
  import android.media.RingtoneManager;
  import android.net.Uri;
  import android.support.v4.app.NotificationCompat;
  import android.util.Log;
  
  import com.google.firebase.messaging.FirebaseMessagingService;
  import com.google.firebase.messaging.RemoteMessage;
  import com.nufdev.firelink.MainActivity;
  import com.nufdev.firelink.R;
  
  public class MyFirebaseMessagingService extends FirebaseMessagingService {
      private static final String TAG = "MyFirebaseMsgService";
  
      /**
       * Called when message is received.
       *
       * @param remoteMessage Object representing the message received from Firebase Cloud Messaging.
       */
      // [START receive_message]
      @Override
      public void onMessageReceived(RemoteMessage remoteMessage) {
  
          Log.d(TAG, "From: " + remoteMessage.getFrom());
  
          // Check if message contains a data payload.
          if (remoteMessage.getData().size() &gt; 0) {
              Log.d(TAG, "Message data payload: " + remoteMessage.getData());
          }
  
          // Check if message contains a notification payload.
          if (remoteMessage.getNotification() != null) {
              Log.d(TAG, "Message Notification Body: " + remoteMessage.getNotification().getBody());
              sendNotification(remoteMessage.getNotification().getBody());
  
          }
  
          // Also if you intend on generating your own notifications as a result of a received FCM
          // message, here is where that should be initiated. See sendNotification method below.
      }
      // [END receive_message]
  
      /**
       * Create and show a simple notification containing the received FCM message.
       *
       * @param messageBody FCM message body received.
       */
      private void sendNotification(String messageBody) {
          Intent intent = new Intent(this, MainActivity.class);
          intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
          PendingIntent pendingIntent = PendingIntent.getActivity(this, 0 /* Request code */, intent,
                  PendingIntent.FLAG_ONE_SHOT);
  
          Uri defaultSoundUri = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
          NotificationCompat.Builder notificationBuilder = new NotificationCompat.Builder(this)
                  .setSmallIcon(R.drawable.icon_send)
                  .setContentTitle("FCM Message")
                  .setContentText(messageBody)
                  .setAutoCancel(true)
                  .setSound(defaultSoundUri)
                  .setContentIntent(pendingIntent);
  
          NotificationManager notificationManager =
                  (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
  
          notificationManager.notify(0 /* ID of notification */, notificationBuilder.build());
      }
  
      @Override
      protected Intent zzaa(Intent intent) {
          Log.v(TAG, "ZZZA?");
          return null;
      }
  }  
  </code></pre>
  
  <p>Whenever I send a notification from the Firebase console I only get in the console: <code>ZZAA</code>? because of this  :  </p>
  
  <pre><code>@Override
          protected Intent zzaa(Intent intent) {
              Log.v(TAG, "ZZZA?");
              return null;
          }
  </code></pre>
  
  <p>I have no idea what <code>zzaa</code> means and can't find it on Google.<br>
  So if you could help me that would be awesome. :D</p>