Java示例-挂起一个线程

public class SleepingThread extends Thread {
   private int countDown = 5;
   private static int threadCount = 0;

   public SleepingThread() {
      super("" + ++threadCount);
      start();
   }

   public String toString() {
      return "#" + getName() + ": " + countDown;
   }

   public void run() {
      while (true) {
         System.out.println(this);
         if (--countDown == 0) return;
         try {
            sleep(100);
         } catch (InterruptedException e) {
            throw new RuntimeException(e);
         }
      }
   }

   public static void main(String[] args) throws InterruptedException {
      for (int i = 0; i < 5; i++) new SleepingThread().join();
      System.out.println("The thread has been suspened.");
   }
}