Which statement is true?

Posted 2020-10-02 美味的花

void waitForSignal()
{
    Object obj = new Object();
    synchronized(Thread.currentThread())
    {
        obj.wait();
        obj.notify();
    }
}

 

This code may throw an InterruptedException

This code may throw an IllegalStateException

This code may throw a TimeOutException after ten minutes

This code will not compile unless”obj.wait()”is replaced with”(Thread)obj).wait()”

Reversing the order of obj.wait()and obj.notify()may cause this method to complete normally

解析：

 

这题有两个错误的地方，第一个错误是 wait() 方法要以 try/catch 包覆，或是掷出 InterruptedException 才行   
因此答案就是因为缺少例外捕捉的   InterruptedException

第二个错误的地方是， synchronized 的目标与 wait() 方法的物件不相同，会有 IllegalMonitorStateException ，不过 InterruptedException 会先出现，所以这不是答案

最后正确的程式码应该是这样：   
  

   void waitForSignal() {

Object obj = new Object();

         synchronized (obj) {

             try {

obj.wait();

} catch (InterruptedException e) {

e.printStackTrace();

}

obj.notify();

}

}