Java并发编程--死锁及模拟银行转账实现_并发安全银行转账java demo

死锁DeadLock

死锁是指两个或两个以上的线程在执行过程中，由于竞争资源或者由于彼此通信而造成的一种阻塞的现象，若无外力作用，它们都将无法推进下去。此时称系统处于死锁状态或系统产生了死锁，这些永远在互相等待的进程称为死锁进程。

public class Lock {
 
	private static Object obj1 = new Object();
	private static Object obj2 = new Object();
 
	public static void main(String[] args) {
		new Thread(() -> {
			try {
				while (true) {
					synchronized (obj1) {
						System.out.println("lock obj1 thread:" + Thread.currentThread().getName());
						Thread.sleep(3000);
						synchronized (obj2) {
							System.out.println("lock obj2 thread:" + Thread.currentThread().getName());
							Thread.sleep(3000);
						}
					}
				}
			}
			catch (Exception e) {
			}
		}
		).start();
		new Thread(() -> {
			try {
				while (true) {
					synchronized (obj2) {
						System.out.println("lock obj2 thread:" + Thread.currentThread().getName());
						Thread.sleep(3000);
						synchronized (obj1