死锁

/** * 一个简单的死锁类* @author iStar * 当类的对象flag=1时（T1），先锁定O1,睡眠500毫秒，然后锁定O2；* 而T1在睡眠的时候另一个flag=0的对象（T2）线程启动，先锁定O2,睡眠500毫秒，等待T1释放O1；* T1睡眠结束后需要锁定O2才能继续执行，而此时O2已被T2锁定；* T2睡眠结束后需要锁定O1才能继续执行，而此时O1已被T1锁定；* T1、T2相互等待，都需要对方锁定的资源才能继续执行，从而死锁。*/class DeadLock implements Runnable { public int flag = 1; static Object o1 = new Object(), o2 = new Object(); @Override public void run() { System.out.println("flag=" + flag); if(flag == 1) { synchronized(o1) { try { Thread.sleep(500); } catch (Exception e) { e.printStackTrace(); } synchronized(o2) { System.out.println("1"); } } } if(flag == 0) { synchronized(o2) { try { Thread.sleep(500); } catch (Exception e) { e.printStackTrace(); } synchronized(o1) { System.out.println("0"); } } } } public static void main(String[] args) { DeadLock td1 = new DeadLock(); DeadLock td2 = new DeadLock(); td1.flag = 1; td2.flag = 0; new Thread(td1).start(); new Thread(td2).start(); } }