title: Understanding android classes and methods
body: <p>Can you explain the following code. 
  I do understand classes , methods in JAVA. I am not able to understand this in android.</p>
  
  <pre><code>  public class MainActivity extends Activity
    {
     protected void onCreate(Bundle savedInstanceState) 
      {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
  
      }
    }
  </code></pre>