title: Firebase realtime database app crashing after uploading on play console
body: <p>My code works perfectly on emulator or mobile through android studio debug mode
  But after uploading on play console i got this error
  App crashing when i try to load data into recyclerview</p>
  <pre><code>com.google.firebase.database.DatabaseException: 
    at com.google.firebase.database.core.utilities.encoding.CustomClassMapper$BeanMapper.&lt;init&gt; (CustomClassMapper.java)
    at com.google.firebase.database.core.utilities.encoding.CustomClassMapper.loadOrCreateBeanMapperForClass (CustomClassMapper.java:12)
    at com.google.firebase.database.core.utilities.encoding.CustomClassMapper.convertBean (CustomClassMapper.java)
    at com.google.firebase.database.core.utilities.encoding.CustomClassMapper.deserializeToClass (CustomClassMapper.java)
    at com.google.firebase.database.core.utilities.encoding.CustomClassMapper.convertToCustomClass (CustomClassMapper.java)
    at com.google.firebase.database.DataSnapshot.getValue (DataSnapshot.java)
    at com.friend.line2.Groups.Groups$2.onDataChange (Groups.java)
    at com.google.firebase.database.Query$1.onDataChange (Query.java)
    at com.google.firebase.database.core.ValueEventRegistration.fireEvent (ValueEventRegistration.java)
    at com.google.firebase.database.core.view.DataEvent.fire (DataEvent.java:2)
    at com.google.firebase.database.core.view.EventRaiser$1.run (EventRaiser.java)
    at android.os.Handler.handleCallback (Handler.java:883)
    at android.os.Handler.dispatchMessage (Handler.java:100)
    at android.os.Looper.loop (Looper.java:264)
    at android.app.ActivityThread.main (ActivityThread.java:7581)
    at java.lang.reflect.Method.invoke (Native Method)
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run (RuntimeInit.java:492)
    at com.android.internal.os.ZygoteInit.main (ZygoteInit.java:980)
  </code></pre>