如果synchronized(new Object){} 和 Object obj = new Object(); synchronized(obj){}的区别是什么? 主要是在synchronized()中放new Object 是四个线程一起,而放obj对象是一个一个的执行,这是什么原因呢?
代码:
class XianChengDemo {
public static void main(String[] args)
{
Card c = new Card();
Thread t = new Thread(c);
Thread t1 = new Thread(c);
Thread t2 = new Thread(c);
Thread t3 = new Thread(c);
t.start();
t1.start();
t2.start();
t3.start();
}}
class Card implements Runnable{
private static int cards = 100;
Object obj = new Object();
public void run()
{ while(true)
{ synchronized(obj)
{ if(cards>0)
{ try{Thread.sleep(10);}catch(Exception e){} System.out.println(Thread.currentThread().getName()+"------"+cards--);
}
else{
break;
}
}
} }}