Calling JS function from the Java code Android

[VivekFitkariwala]

Hi I have followed this tutorial http://cocos2d-x.org/docs/manual/framework/html5/v3/reflection/en but I am not able to send message back to JS.
I have added the class Cocos2dxJavascriptJavaBridge inside org.cocos2dx.javascript package of the project but my app crashes when executing at this point.
code below is

package org.cocos2dx.javascript;

import org.cocos2dx.Test1.R;
import org.cocos2dx.lib.Cocos2dxActivity;
import org.cocos2dx.lib.Cocos2dxGLSurfaceView;

import android.app.AlertDialog;
import android.content.DialogInterface;
import android.os.Bundle;

public class AppActivity extends Cocos2dxActivity {
private static AppActivity app = null;

@Override
public Cocos2dxGLSurfaceView onCreateView() {
    Cocos2dxGLSurfaceView glSurfaceView = new Cocos2dxGLSurfaceView(this);
    // TestCpp should create stencil buffer
    glSurfaceView.setEGLConfigChooser(5, 6, 5, 0, 16, 8);

    return glSurfaceView;
}

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    app = this;
}

public static void showAlertDialog(final String title,final String message) {

    //we must use runOnUiThread here
    app.runOnUiThread(new Runnable() {
        @Override
        public void run() {
            AlertDialog alertDialog = new AlertDialog.Builder(app).create();
            alertDialog.setTitle(title);
            alertDialog.setMessage(message);
            alertDialog.setIcon(R.drawable.icon);
            alertDialog.show();
            alertDialog.setButton("OK", new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int which) {

                    //we must use runOnGLThread here
                    app.runOnGLThread(new Runnable() {
                        @Override
                        public void run() {
                            Cocos2dxJavascriptJavaBridge.evalString("cc.log(\"JavaScript Java bridge!\")");
                        }
                    });
                }
            });
        }
    });
}

}