title: how to start service in android without an activity
body: <p>i am beginner at android. I have two class, and first class is</p>
  
  <pre><code>public class SmsReceiver extends BroadcastReceiver{}
  </code></pre>
  
  <p>And the second class is </p>
  
  <pre><code>public class SMS extends Activity{}
  </code></pre>
  
  <p>All I want to do that : when I get an SMS, start activity and do something. But i want to use "service" instead of "activity". I mean when application start, then start service without activity. </p>
  
  <p>is this possible ?</p>