Your help needed: sychronized method behaving wrong

Question

//sychronized method behaving wrong:
/*expected synchronized output:
Thread-x: begin
Thread-x: end
Thread-y: begin
Thread-y: end
/*actual un-synchronized output:
Thread-x: begin
Thread-y: begin
Thread-x: end
Thread-y: end
//what's wrong with the following code snippet about sychronized method? Thx!
class Test implements Runnable {
     public void run() {
               doo();          
     private synchronized void doo() {
          System.out.println(Thread.currentThread().getName() + ": begin");
          try { Thread.sleep(new java.util.Random().nextInt(10));} catch (Exception e) {}
          System.out.println(Thread.currentThread().getName() + ": end");     
     public static void main(String[] args) {
          Test[] tests = new Test[10];
          Thread[] tt = new Thread[10];
          for (Test test:tests) new Thread(new Test()).start();
}

Answer 1

oops! changing the thread initialization has sloved the problem, cauz synchronized method applies to the same object executing multiple threads.
...main...{
Test t = new Test();
for (int i=0;i<10;i++) new Thread(t).start();
}