title: Inside a class extends thread. Where to put another class creation?
body: <p>I have two classes, 
  Class_A is to accept packets. (with multi-threads)
  Class_B is to parse each time packets received.
  What I want to do is to let Class_A create new thread when there is new coming packet.
  and each Class_A thread will create Class_B instance to parse the packets.</p>
  
  <pre><code>    public class Class_A extends Thread{
  
        public Class_A(){
  
        }
  
        public void run() {
          Class_B B=new ClassB();
          B.xxxxxxx;
        }
      }
  </code></pre>
  
  <p>I wonder if there is a any difference or better to create B instance in the constructor? 
  Or at the beginning of Class_A?</p>
  
  <p>Thank you</p>