上面的代码看起来是没有问题的：锁定两个账户来判断余额是否充足才进行转账！
但是，同样有可能会发生死锁：
如果两个线程同时调用transferMoney()
线程A从X账户向Y账户转账
线程B从账户Y向账户X转账
那么就会发生死锁 。
协作对象之间发生死锁public class CooperatingDeadlock { // Warning: deadlock-prone! class Taxi { @GuardedBy("this") private Point location, destination; private final Dispatcher dispatcher; public Taxi(Dispatcher dispatcher) { this.dispatcher = dispatcher; } public synchronized Point getLocation() { return location; } // setLocation 需要Taxi内置锁 public synchronized void setLocation(Point location) { this.location = location; if (location.equals(destination)) // 调用notifyAvailable()需要Dispatcher内置锁 dispatcher.notifyAvailable(this); } public synchronized Point getDestination() { return destination; } public synchronized void setDestination(Point destination) { this.destination = destination; } } class Dispatcher { @GuardedBy("this") private final Set<Taxi> taxis; @GuardedBy("this") private final Set<Taxi> availableTaxis; public Dispatcher() { taxis = new HashSet<Taxi>(); availableTaxis = new HashSet<Taxi>(); } public synchronized void notifyAvailable(Taxi taxi) { availableTaxis.add(taxi); } // 调用getImage()需要Dispatcher内置锁 public synchronized Image getImage() { Image image = new Image(); for (Taxi t : taxis) // 调用getLocation()需要Taxi内置锁 image.drawMarker(t.getLocation()); return image; } } class Image { public void drawMarker(Point p) { } }}上面的getImage()和setLocation(Point location)都需要获取两个锁的
并且在操作途中是没有释放锁的 这就是隐式获取两个锁(对象之间协作)..
这种方式也很容易就造成死锁.....
避免死锁：在有些情况下死锁是可以避免的 。本文将展示三种用于避免死锁的技术：
![[技时]起售价3999元，小米10系列迎来强敌！一加8系列发布](https://imgcdn.toutiaoyule.com/20200416/20200416204402482498a_t.jpeg)
