How to get email id From Android Facebook SDK 4.6.0?

Here is my code for getting user information after facebook login. I am trying to get emailid from user I am getting Name , id , but not getting the emailid .I have tried with the Login Button and Login Manager class both giving the same results . Now how to get email id from response :

loginButton.registerCallback(callbackManager, new FacebookCallback<LoginResult>() {
                @Override
                public void onSuccess(final LoginResult loginResult) {
                    new GraphRequest(AccessToken.getCurrentAccessToken(),
                            "/me", null , HttpMethod.GET,
                            new GraphRequest.Callback() {
                                public void onCompleted(
                                        GraphResponse response) {
                                         handle the result 

                                    if (response !=null  )
                                    {
                                        //GET USER INFORMATION
                                        Toast.makeText(getApplicationContext(),"Hello in JSON",Toast.LENGTH_LONG).show();
                                        JSONObject json = response.getJSONObject();
                                        //JSONArray jsona = response.getJSONArray();
                                        Log.i(TAG,"" +json);
                                       // Log.i(TAG,"" +json);
                                        String email = json.optString("email");
                                       // String email = json.optString("email");
                                        //Log.i("email", "" + email);
                                        Log.i(TAG,"" +email);
                                        String fullName = json.optString("name");
                                        String location = json.optString("location");
                                        String accessToken = loginResult.getAccessToken().getToken();
                                        String user_id = json.optString("id");
                                        Log.i(TAG,"" +json);
                                        Toast.makeText(getApplicationContext(),fullName,Toast.LENGTH_LONG).show();
                                        Toast.makeText(getApplicationContext(),email,Toast.LENGTH_LONG).show();
                                        Toast.makeText(getApplicationContext(),user_id,Toast.LENGTH_LONG).show();
                                        //int type = 1;
                                       // String lastUpdate = json.getString("updated_time");

                                      //  Log.i("email", "" + email);
                                      //  Log.i("Message", "HELLO");
                                        Log.i("Name", "" + fullName);
                                        Log.i("ID", "" + user_id);


                                    }
                                }

                            }).executeAsync();

Thanks..!!

LoginManager.getInstance().logInWithReadPermissions(WelcomeActivity1.this, (Arrays.asList("public_profile", "user_friends","user_birthday","user_about_me","email")));

String email;


LoginManager.getInstance().registerCallback(callbackManager,new FacebookCallback<LoginResult>() {
 @Override
  public void onSuccess(LoginResult loginResult) {
  Log.d("tag","FF fb onSuccess");
  GraphRequest request = GraphRequest.newMeRequest(loginResult.getAccessToken(),new GraphRequest.GraphJSONObjectCallback() {
    @Override
    public void onCompleted(JSONObject object,GraphResponse response) {
     try {
           String[] splited ;
           JSONObject obj =  object.getJSONObject("picture").getJSONObject("data");

                              if (object.has("email"))
                              {
                                 email =  object.getString("email");
                              }
                              else
                              {
                                  email = "";
                              }



                            } catch (JSONException e) {
                                // TODO Auto-generated catch block
                                e.printStackTrace();
                            }


                            }
                        });
                Bundle parameters = new Bundle();
                parameters.putString("fields", "id,name,link,birthday,picture,email,gender");
                request.setParameters(parameters);
                request.executeAsync();


            }

            @Override
            public void onCancel() {
                Log.d("tag","fb onCancel");
                 // App code
            }



@Override
            public void onError(FacebookException exception) {
                Log.d("tag","fb onError");
                 // App code   
            }
});