public class PingPong extends Thread {
   String word;                 // what word to print
   int delay;                   // how long to pause
   int count;                   // number of iterations

   PingPong(String what, int time, int number) {
      word = what;
      delay = time;
      count = number;
      try {
         setName(what);
      }
      catch (SecurityException e) {
         System.out.println("Warning: could not set the name of thread "+what);
      }
   }

   public void run() {
      try {
         for(int i=0;i<count;i++) {
            System.out.println(i+": "+word+":"+activeCount());
            sleep(delay);    // wait until next time
         }
      }  catch (InterruptedException e) {
         return;                 // end this thread
      }
   }
}