Java ThreadGroup(ThreadGroup parent, String name) Constructor

public ThreadGroup(ThreadGroup parent,    String name)

/*from  w  w  w .  ja  v  a  2 s.c o m*/
class MyThread extends Thread {
   MyThread(ThreadGroup group, String name) {
      super(group, name);
   }

   public void run() {
      System.out.println(Thread.currentThread().getName() + " starting.");
      try {
        Thread.sleep(5000);
      }
      catch(Exception e) {
         System.out.print(Thread.currentThread().getName());
         System.out.println(" interrupted.");
      }
      System.out.println(Thread.currentThread().getName() + " exiting.");
   }
}

public class Main {

   public static void main(String args[]) throws Exception {

     ThreadGroup group = new ThreadGroup("Group");

     ThreadGroup newGroup = new ThreadGroup(group,"new group");
     
     MyThread t1 = new MyThread(group, "Thread1");
     MyThread t2 = new MyThread(group, "Thread2");
   
     t1.start();
     t2.start();
   
     Thread.sleep(1000);

     System.out.println(group.activeCount() + " threads in thread group...");

     Thread th[] = new Thread[group.activeCount()];
     group.enumerate(th);
     for(Thread t : th){
        System.out.println(t.getName());
     }
     Thread.sleep(1000);
    
     System.out.println(group.activeCount() + " threads in thread group...");

     group.interrupt();
  }
}