java 中多线程死锁问题

[IT痴者]

这个程序为什么不能实现死锁？？？？？？？？？？？？




class Dead implements Runnable
{
private boolean flag;
Dead(boolean falg)
{
this.flag = flag;
}
public void run()
{
if (flag)
{
while (true)
{
synchronized(Locks.obj1)
{
System.out.println("if 1 启动！");
synchronized(Locks.obj2)
{
System.out.println("if 2 启动!");
}
}
}
}
else
{
while (true)
{
synchronized(Locks.obj2)
{
System.out.println("else 2 启动！");
synchronized(Locks.obj1)
{
System.out.println("else 1 启动！");
}
}
}
}
}

}

class Locks//定义锁对象
{
static Object obj1 = new Object();
static Object obj2 = new Object();
}

class DeadLock
{
public static void main(String[] args)
{
Thread t1 = new Thread(new Dead(true));
Thread t2 = new Thread(new Dead(false));

t1.start();
t2.start();

}
}

[IT痴者]

[Quote=引用 2 楼 的回复:]

因为Dead(flag)写错了

Java code

class Dead implements Runnable
{
private boolean flag;

Dead(boolean flag) //你写成falg了
{
this.flag = flag;
}

public void run()
……
[/Quote]
那为啥编译成功了呢？？？

[cstur4]

this.flag = flag;这里的flag都是指字段flag,逻辑上有问题，但语法上没问题

[IT痴者]

[Quote=引用 2 楼 的回复:]

因为Dead(flag)写错了

Java code

class Dead implements Runnable
{
private boolean flag;

Dead(boolean flag) //你写成falg了
{
this.flag = flag;
}

public void run()
……
[/Quote]

哈哈 可以了
谢谢啦、、、
为什么编译可以通过呢？？？？？

[IT痴者]

[Quote=引用 5 楼 的回复:]

this.flag = flag;这里的flag都是指字段flag,逻辑上有问题，但语法上没问题
[/Quote]
似乎明白了
谢谢啊

[IT痴者]

class Dead implements Runnable
{
private boolean flag;
Dead(boolean falg)
{
this.flag = flag;
}
public void run()
{
if (flag)
{
while (true)
{
synchronized(Locks.obj1)
{
System.out.println("if 1 启动！");
synchronized(Locks.obj2)
{
System.out.println("if 2 启动!");
}
}
}
}
else
{
while (true)
{
synchronized(Locks.obj2)
{
System.out.println("else 2 启动！");
synchronized(Locks.obj1)
{
System.out.println("else 1 启动！");
}
}
}
}
}

}

class Locks//定义锁对象
{
static Object obj1 = new Object();
static Object obj2 = new Object();
}

class DeadLock
{
public static void main(String[] args)  
{
Thread t1 = new Thread(new Dead(true));
Thread t2 = new Thread(new Dead(false));

t1.start();
t2.start();

}
}

[枫叶红了]

找个视频看看吧，代码的问题还得自己去理解，梳理思路

[周靖峰]

因为Dead(flag)写错了

class Dead implements Runnable
{
	private boolean flag;
	
	Dead(boolean flag)	//你写成falg了
	{
		this.flag = flag;
	}
	
	public void run()
	{
		if (flag)
		{
			while (true)
			{
				synchronized(Locks.obj1)
				{
					System.out.println("if 1 启动！");
					synchronized(Locks.obj2)
					{
						System.out.println("if 2 启动!");
					}
				}
			}
		}
		else
		{
			while (true)
			{
				synchronized(Locks.obj2)
				{
					System.out.println("else 2 启动！");
					synchronized(Locks.obj1)
					{
						System.out.println("else 1 启动！");
					}
				}
			}
		}
	}

}

class Locks//定义锁对象
{
	static Object obj1 = new Object();
	static Object obj2 = new Object();
}

class DeadLock
{
	public static void main(String[] args) 
	{
		Thread t1 = new Thread(new Dead(true));
		Thread t2 = new Thread(new Dead(false));
		
		t1.start();
		t2.start();
	
	}
}

[孤雨]

Dead(boolean falg)
{
this.flag = flag;
}

主要还是你不太小心了，这块有点小错误，应该都是flag。这样创建对象调用构造方法时值没有传就去，所以就是其boolean的默认值false。导致没法得到自己想要的结果，加油。