java线程synchronized(this){}为何对其它synchronized方法产生影响。

Question

直接上代码：

public class NewThread implements Runnable{

String name;
Thread t;
static boolean suspendFlag;

NewThread(String threadname)
{
    name=threadname;
    t=new Thread(this,name);
    System.out.println("New thread:"+t);
    suspendFlag=false;
    t.start();
}

public void run()
{

    try
    {

        for(int i=15;i>0;i--)
    {

            System.out.println(name+":"+i);

    Thread.sleep(1000);
    synchronized(this){while(suspendFlag){this.wait();}}


    }   
    }catch(InterruptedException e){}

    System.out.println(name+" exiting.");

    }

synchronized  void mysuspend(){suspendFlag=true;}
synchronized  void myresume(){suspendFlag=false;notify();}

}

public class SuspendResume {

/**
 * @param args
 */
public static void main(String[] args) {
    // TODO Auto-generated method stub

NewThread ob1=new NewThread("One");

try{
Thread.sleep(2000);

ob1.mysuspend();
System.out.println("Suspending thread One");
Thread.sleep(2000);


ob1.myresume();
System.out.println("Resuming thread One");

Thread.sleep(2000);

}catch(InterruptedException e){}

try{System.out.println("Waiting for threads to finiish.");
ob1.t.join();

}catch(InterruptedException e){}

System.out.println("Main thread exiting.");

}

}
运行结果：
New thread:Thread[One,5,main]
One:15
One:14
One:13
Suspending thread One
One:12
Resuming thread One
One:11
One:10
Waiting for threads to finiish.
One:9
One:8
One:7
One:6
One:5
One:4
One:3
One:2
One:1
One exiting.
Main thread exiting.
如预期一样，ob1.mysuspend();ob1.myresume();的调用在ob1线程运行中是正常时间控制挂起和重启。
但将run()方法中synchronized(this){}模块稍微修改：
public void run()
{

    try
    {
        synchronized(this){
        for(int i=15;i>0;i--)
    {

            System.out.println(name+":"+i);

    Thread.sleep(1000);
    while(suspendFlag){this.wait();}


    }
        }
    }catch(InterruptedException e){}

    System.out.println(name+" exiting.");

    }


    其余代码不变

结果是：
New thread:Thread[One,5,main]
One:15
One:14
One:13
One:12
One:11
One:10
One:9
One:8
One:7
One:6
One:5
One:4
One:3
One:2
One:1
Suspending thread One
One exiting.
Resuming thread One
Waiting for threads to finiish.
Main thread exiting.

结果是主线程对ob1.mysuspend();ob1.myresume();的调用没有按照预期的时间进行，而是卡在ob1线程运行结束后才开始调用，就好像ob1得运行将ob1.mysuspend();ob1.myresume();锁住一样，sychonized模块将循环体包围住，mysuspend()就像被锁住不能动了似的，为什么会有两次的运行结果差异？谢谢。

Answer 1

第二种情况的结果的末尾：
One:2
One:1 //线程ob1在synchronized模块中的输出内容。
Suspending thread One //主线程成功调用了ob1.mysuspend()的输出。
One exiting. //线程ob1在synchronized模块外输出内容。

主线程非常巧合的再线程执行完最后一个synchronized模块输出后开始启动。主线程再”等待”ob1中synchroized()模块的结束，双方是互相独立的synchronized锁代码，
怎么会互相等待的呢。