多线程_死锁

死锁：通常同步中嵌套不同，而且锁不同

 1 public class DeadlockDemo {

 2     public static void main(String[] args) {

 3         Demo d1 = new Demo(true);

 4         Demo d2 = new Demo(false);

 5          

 6         Thread t1 = new Thread(d1);

 7         Thread t2 = new Thread(d2);

 8 

 9         t1.start();

10         t2.start();

11         

12     }

13 }

14 class Demo implements Runnable{

15     private boolean flag;

16     Demo(boolean flag){

17         this.flag = flag;

18     }

19     public void run(){

20         if(flag){

21             synchronized(MyLock.locka){

22                 System.out.println("if locka....");

23                 synchronized(MyLock.lockb){

24                     System.out.println("if lockb....");

25                 }

26             }

27         }

28         else{

29             synchronized(MyLock.lockb){

30                 System.out.println("else lockb....");

31                 synchronized(MyLock.locka){

32                     System.out.println("else locka....");

33                 }

34             }

35         }

36     }

37 }

38 class MyLock{

39     public static final Object locka = new Object();

40     public static final Object lockb = new Object();

41 }