title: Can't convert object of type java.util.ArrayList to type model
body: <p>I'm trying to load data to RecycleView from Firebase. But I get convert error.</p>
  
  <pre><code>com.google.firebase.database.DatabaseException: Can't convert object of type java.util.ArrayList to type uk.co.stableweb.kithunugee.model.Hymn
       at com.google.android.gms.internal.zzaix.zzd(Unknown Source)
       at com.google.android.gms.internal.zzaix.zzb(Unknown Source)
       at com.google.android.gms.internal.zzaix.zza(Unknown Source)
       at com.google.firebase.database.DataSnapshot.getValue(Unknown Source)
       at com.google.firebase.database.DataSnapshot.getValue(Unknown Source)  
       at com.firebase.ui.database.FirebaseRecyclerAdapter.parseSnapshot(FirebaseRecyclerAdapter.java:147)
       at com.firebase.ui.database.FirebaseRecyclerAdapter.getItem(FirebaseRecyclerAdapter.java:136)
       at com.firebase.ui.database.FirebaseRecyclerAdapter.onBindViewHolder(FirebaseRecyclerAdapter.java:176)
       at android.support.v7.widget.RecyclerView$Adapter.onBindViewHolder(RecyclerView.java:5471)
       at android.support.v7.widget.RecyclerView$Adapter.bindViewHolder(RecyclerView.java:5504)
       at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:4741)
       at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:4617)
       at android.support.v7.widget.LinearLayoutManager$LayoutState.next(LinearLayoutManager.java:1994)
       at android.support.v7.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1390)
       at android.support.v7.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1353)
       at android.support.v7.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:574)
       at android.support.v7.widget.RecyclerView.dispatchLayoutStep2(RecyclerView.java:3028)
       at android.support.v7.widget.RecyclerView.onMeasure(RecyclerView.java:2625)
       at android.view.View.measure(View.java:18850)
       at android.widget.RelativeLayout.measureChildHorizontal(RelativeLayout.java:716)
       at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:462)
       at android.view.View.measure(View.java:18850)
       at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5956)
       at android.support.design.widget.CoordinatorLayout.onMeasureChild(CoordinatorLayout.java:668)
       at android.support.design.widget.HeaderScrollingViewBehavior.onMeasureChild(HeaderScrollingViewBehavior.java:90)
       at android.support.design.widget.AppBarLayout$ScrollingViewBehavior.onMeasureChild(AppBarLayout.java:1192)
       at android.support.design.widget.CoordinatorLayout.onMeasure(CoordinatorLayout.java:733)
       at android.view.View.measure(View.java:18850)
       at android.support.v4.widget.DrawerLayout.onMeasure(DrawerLayout.java:1075)
       at android.view.View.measure(View.java:18850)
       at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5956)
       at android.widget.FrameLayout.onMeasure(FrameLayout.java:194)
       at android.support.v7.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:135)
       at android.view.View.measure(View.java:18850)
       at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5956)
       at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1465)
       at android.widget.LinearLayout.measureVertical(LinearLayout.java:748)
       at android.widget.LinearLayout.onMeasure(LinearLayout.java:630)
       at android.view.View.measure(View.java:18850)
       at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5956)
       at android.widget.FrameLayout.onMeasure(FrameLayout.java:194)
       at android.view.View.measure(View.java:18850)
       at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5956)
       at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1465)
       at android.widget.LinearLayout.measureVertical(LinearLayout.java:748)
       at android.widget.LinearLayout.onMeasure(LinearLayout.java:630)
       at android.view.View.measure(View.java:18850)
       at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5956)
       at android.widget.FrameLayout.onMeasure(FrameLayout.java:194)
       at com.android.internal.policy.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2671)
       at android.view.View.measure(View.java:18850)
       at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2107)
  </code></pre>
  
  <p>This is how I load data from RecycleView.</p>
  
  <pre><code>DatabaseReference ref = FirebaseDatabase.getInstance().getReference();
  mRecyclerViewAdapter = new FirebaseRecyclerAdapter&lt;Hymn, HymnHolder&gt;(Hymn.class, R.layout.hymn_row, HymnHolder.class, ref) {
         @Override
         protected void populateViewHolder(HymnHolder viewHolder, Hymn hymn, int position) {
                viewHolder.setTitle(hymn.getTitle());
                viewHolder.setIndex(String.valueOf(hymn.getIndex()));
        }
  };
  
  // Scroll to bottom on new messages
  mRecyclerViewAdapter.registerAdapterDataObserver(new RecyclerView.AdapterDataObserver() {
         @Override
         public void onItemRangeInserted(int positionStart, int itemCount) {
                mLayoutManager.smoothScrollToPosition(recyclerView, null, mRecyclerViewAdapter.getItemCount());
         }
  });
  
  recyclerView.setAdapter(mRecyclerViewAdapter);
  </code></pre>
  
  <p>And my ViewHolder class is,</p>
  
  <pre><code>public class HymnHolder extends RecyclerView.ViewHolder {
      View mView;
  
      public HymnHolder(View itemView) {
          super(itemView);
          mView = itemView;
      }
  
      public void setTitle(String name) {
          TextView field = (TextView) mView.findViewById(R.id.title);
          field.setText(name);
      }
  
      public void setIndex(String index) {
          TextView field = (TextView) mView.findViewById(R.id.index);
          field.setText(index);
      }
  }
  </code></pre>
  
  <p>And this is my model.</p>
  
  <pre><code>public class Hymn {
      private int index;
      private String title;
      private String content;
  
      public int getIndex() {
          return index;
      }
  
      public void setIndex(int index) {
          this.index = index;
      }
  
      public String getTitle() {
          return title;
      }
  
      public void setTitle(String title) {
          this.title = title;
      }
  
      public String getContent() {
          return content;
      }
  
      public void setContent(String content) {
          this.content = content;
      }
  
  }
  </code></pre>
  
  <p>Here is the structure of my Firebase database.</p>
  
  <p><a href="https://i.stack.imgur.com/Mlr1F.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Mlr1F.png" alt="enter image description here"></a></p>
  
  <p>I refered <a href="https://github.com/firebase/FirebaseUI-Android/blob/master/database/README.md" rel="nofollow noreferrer">this</a> Firebase UI tutorial. There were few previous questions regarding this problem, but it's not clear to me. If you have any hint on this issue, it would be really helpful.</p>