Java 多线程 ThreadGroup

package thread.group;

public class SayThread extends Thread {
  
  public SayThread(ThreadGroup group, String name) {
    super(group, name);
  }

  public void run() {
    for (int i = 0; i < 5; i++) {
      System.out.println(getName() + " = " + i);
      try {
        sleep(200);
      } catch (InterruptedException e) {
        Thread.currentThread().interrupt();
      }
    }
    System.out.println(getName() + " done");
  }
}

package thread.group;

public class Test {
  /**
   * @author jzh add 2011-12-20
   * @param args
   */
  public static void main(String args[]) {
    ThreadGroup group = new ThreadGroup("groupThread");
    SayThread howskyThread = new SayThread(group, "jiang");
        SayThread jzhThread = new SayThread(group, "jzh");
    SayThread sayThread = new SayThread(group, "say");
    
    howskyThread.start();
    jzhThread.start();
    sayThread.start();

    System.out.println("the number of active threads = " + group.activeCount());

    // Copies into the specified array every active thread in this thread group and its subgroups.
    Thread[] list = new Thread[group.activeCount()];
    group.enumerate(list);

    for (Thread thread : list) {
      System.out.println(thread.getName());
    }
  }
}