setLayoutManager NullPointException in RecyclerView

Question

I'm trying to receive a list with an array in RecyclerView and get error:

java.lang.NullPointerException: Attempt to invoke virtual method  'void android.support.v7.widget.RecyclerView.setLayoutManager (android.support.v7.widget.RecyclerView$LayoutManager)'on a null object reference 

RecyclerView widget's

   <android.support.v7.widget.RecyclerView         android:id="@+id/drawerList"         android:layout_width="match_parent"         android:layout_height="wrap_content">     </android.support.v7.widget.RecyclerView> 

I tried to declare LayoutManager to final, but it doesn't help.

Activity code:

public class MainActivity extends ActionBarActivity {  private RecyclerView recyclerView; private Toolbar toolbar; private InfAdapter adapter;   @Override protected void onCreate (Bundle savedInstanceState) {     super.onCreate (savedInstanceState);     setContentView (R.layout.activity_main_appbar);      recyclerView = (RecyclerView) findViewById(R.id.drawerList);      recyclerView.setLayoutManager(new LinearLayoutManager(this));      InfAdapter mAdapter = new InfAdapter(this, getData());     recyclerView.setAdapter(mAdapter);     recyclerView.setItemAnimator(new DefaultItemAnimator());      toolbar = (Toolbar) findViewById(R.id.app_bar);     setSupportActionBar(toolbar);     getSupportActionBar().setDisplayShowHomeEnabled(true);  } 

Adapter code:

public class InfAdapter extends RecyclerView.Adapter<InfAdapter.MyViewHolder> {    private final Context context;     private  List<Information> data = Collections.emptyList();       public InfAdapter(Context context, List<Information> data){         this.data = data;         this.context = context;     }      @Override     public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {         View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.custom_row, parent, false);         return new MyViewHolder(v);     }       @Override     public void onBindViewHolder(MyViewHolder  holder, int position) {          Information current  = data.get(position);         holder.title.setText(current.title);         holder.icon.setImageResource(current.iconid);     }       @Override     public int getItemCount() {         return data.size();     }      class MyViewHolder extends RecyclerView.ViewHolder{     TextView title;     ImageView icon;      public MyViewHolder(View itemView) {          super(itemView);         title = (TextView) itemView.findViewById(R.id.listText);         icon = (ImageView) itemView.findViewById(R.id.listIcon);          }     } } 

What has possibly gone wrong?