i wont my request url abc.com/xyz or abc.com/mobile or abc.com/smartphone
i want to get response myController and action helloworld
mean if my request url is not an controller just get response from myController and action helloworld but not changing browser URl (not redirect )
You need to define custom routes to map any URL to any controller and any action.
See the cookbook: http://book.cakephp.org/2.0/en/development/routing.html
If that doesn't do what you need, you could use URL rewriting but that would be specific to your webserver.
Solve this problem in rotes.php
by adding
$routes->connect('/home/xxx/test', ['controller' => 'home', 'action' =>'index' ]);