 the 
class is compiled. <i>classname</i> must contain a  <code>main()</code> 
method, which 
<b>java</b> executes and then exits, unless <code>main()</code> 
creates one or more threads. If any threads are created by <code>main()</code>
then <b>java</b> doesn't exit until the last thread exits. The 
<code>main()</code> method is defined as follows:
<pre>
    class Aclass {
        public static void main(String argv[]){ 
            < main code >
        }
    }
</pre>
When you define your own classes you 