title: Android intent service crashing on firebase database reference
body: <p>I am developing an Android application in which I am using an intent service to update locations to my firebase project with a certain periodicity. But it seems that I have hit a wall quite early. When I give the root reference of my firebase database in the service, it crashes.</p>
  
  <p>When I use this code:</p>
  
  <pre><code>import android.app.IntentService;
  import android.content.Intent;
  import com.google.firebase.database.DatabaseReference;
  import com.google.firebase.database.FirebaseDatabase;
  
  public class LocationUpdater extends IntentService{
  
      public LocationUpdater() {
          super("LocationUpdater");
      }
  
      @Override
      protected void onHandleIntent(Intent intent) {
          synchronized (this){
              try{
                  wait(2000);
              }catch (InterruptedException e){
                  e.printStackTrace();
              }
          }
  
      }
  }
  </code></pre>
  
  <p>which does nothing, it is fine. But when I add this single line:</p>
  
  <pre><code>private DatabaseReference mRoot = FirebaseDatabase.getInstance().getReference();
  </code></pre>
  
  <p>just above the LocationUpdater constructor, the app crashes. Any ideas on why this is happening? 
  Thanks in advance!</p>
  
  <p>This is the error output in logcat:</p>
  
  <pre><code>java.lang.RuntimeException: Unable to instantiate service com.mohana.cluster.LocationUpdater: java.lang.IllegalStateException: Default FirebaseApp is not initialized in this process com.mohana.cluster. Make sure to call FirebaseApp.initializeApp(Context) first.
                                                                          at android.app.ActivityThread.handleCreateService(ActivityThread.java:3168)
                                                                          at android.app.ActivityThread.-wrap5(ActivityThread.java)
                                                                          at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1563)
                                                                          at android.os.Handler.dispatchMessage(Handler.java:102)
                                                                          at android.os.Looper.loop(Looper.java:154)
                                                                          at android.app.ActivityThread.main(ActivityThread.java:6123)
                                                                          at java.lang.reflect.Method.invoke(Native Method)
                                                                          at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:867)
                                                                          at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:757)
                                                                       Caused by: java.lang.IllegalStateException: Default FirebaseApp is not initialized in this process com.mohana.cluster. Make sure to call FirebaseApp.initializeApp(Context) first.
                                                                          at com.google.firebase.FirebaseApp.getInstance(Unknown Source)
                                                                          at com.google.firebase.database.FirebaseDatabase.getInstance(Unknown Source)
                                                                          at com.mohana.cluster.LocationUpdater.&lt;init&gt;(LocationUpdater.java:11)
                                                                          at java.lang.Class.newInstance(Native Method)
                                                                          at android.app.ActivityThread.handleCreateService(ActivityThread.java:3165)
                                                                          at android.app.ActivityThread.-wrap5(ActivityThread.java) 
                                                                          at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1563) 
                                                                          at android.os.Handler.dispatchMessage(Handler.java:102) 
                                                                          at android.os.Looper.loop(Looper.java:154) 
                                                                          at android.app.ActivityThread.main(ActivityThread.java:6123) 
                                                                          at java.lang.reflect.Method.invoke(Native Method) 
                                                                          at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:867) 
                                                                          at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:757) 
  </code></pre>