import java.util.concurrent.*; 

class JoinP {

   public static void main(String[] args) {
      int numberofthreads = 10;
      Thread[] t = new Thread[numberofthreads];

      for (int j = 0; j < numberofthreads; j++) {
         (t[j] = new Thread( new ExThread() )).start();
      }

      try {
         for (int k = 0; k < numberofthreads; k++) t[k].join();
      } catch (Exception e) { return; }

   }

   static class ExThread implements Runnable {

      public void run() {
         try {
            TimeUnit.SECONDS.sleep(10);
         } catch (Exception e) { return;};
      }

   }

}