public class Easy {

String a ;
String q ;
String r ;


public Easy()
{
    this.q = "" ;
    this.a = "" ;
    this.r = "" ;
}
 //getters and setters below

}

public void generateData(int index)
  {
       //URL is root url
     final Firebase firebase = new Firebase(FirebaseConfig.URL) ;

   //for the first time index is 1 , then I increment it when I need
   //next query

   //I have not only EasyQuestions child and I have also another
   // severalchilds

   firebase.child("EasyQuestions").
   child(String.valueOf(index)).addValueEventListener(new
   ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
         Easy easy = new Easy();
        //I get error below
        easy = dataSnapshot.getValue(Easy.class) ;
    }

    @Override
    public void onCancelled(FirebaseError firebaseError) {

    }
});
  }