Java编写一个死锁的程序

死锁是在多线程编程中常常遇到的问题，现在用java编写一个简单的死锁程序。

程序在main()方法中启动2个线程，“线程-A”和“线程-B”。 线程-A 先拿到 lockA，再寻求拿到 lockB；线程-B 先拿到locB，再需求拿到lockA，如下图，于是变成循环等待，造成死锁。

代码如下：

public class DeadLockDemo {

	public static void main(String[] args) {
		Object lockA = new Object();
		Object lockB = new Object();
		new Thread(new Runnable() {
			@Override
			public void run() {
				String name = Thread.currentThread().getName();
				synchronized (lockA) {
					System.out.println(name + " got lockA,  want LockB");
					try {
						Thread.sleep(100);
					} catch (InterruptedException e) {

						e.printStackTrace();
					}
					synchronized (lockB) {
						System.out.println(name + " got lockB");
						System.out.println(name + ": say Hello!");
					}
				}
			}
		}, "线程-A").start();

		new Thread(new Runnable() {
			@Override
			public void run() {

				String name = Thread.currentThread().getName();
				synchronized (lockB) {
					System.out.println(name + " got lockB, want LockA");
					try {
						Thread.sleep(100);
					} catch (InterruptedException e) {

						e.printStackTrace();
					}
					synchronized (lockA) {
						System.out.println(name + " got lockA");
						System.out.println(name + ": say Hello!");
					}
				}

			}
		}, "线程-B").start();
	}
}

运行结果：

线程-A got lockA,  want LockB
线程-B got lockB, want LockA