java线程

public class TestSync implements Runnable {
  Timer timer = new Timer();
  public static void main(String[] args) {
    TestSync test = new TestSync();
    Thread t1 = new Thread(test);
    Thread t2 = new Thread(test);
    t1.setName("t1");
    t2.setName("t2");
    t1.start();
    t2.start();
  }
  public void run(){
    timer.add(Thread.currentThread().getName());
  }
}

class Timer{
  private static int num = 0;
  public synchronized void add(String name){
  //synchronized (this) {
    num ++;
    try {Thread.sleep(1);}
    catch (InterruptedException e) {}
    System.out.println(name+", 你是第"+num+"个使用timer的线程");
  //}
  }
}