Is not a concrete class AndroidManifest
<p>I am getting an error with not a concrete class when I add the Activity in the AndroidManifest. Please help me figure out the problem by removing abstract class for the activity but it doesn't resolve.</p>

<pre><code>public abstract class MapsActivity extends FragmentActivity implements OnMapReadyCallback {
    private GoogleMap mMap;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.map_fragment);
        setUpMap();
    }

    @Override
    protected void onResume() {
        super.onResume();
        setUpMap();
    }

    @Override
    public void onMapReady(GoogleMap map) {
        if (mMap != null) {
            return;
        }
        mMap = map;
        startDemo();
    }

    private void setUpMap() {
        ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map)).getMapAsync(this);
    }

    /**
     * Run the demo-specific code.
     */
    protected abstract void startDemo();

    protected GoogleMap getMap() {
        return mMap;
    }

}
</code></pre>