Java基础之线程5-线程同步死锁

Posted 2020-12-15 risuschen

死锁：线程之间因条件相互竞争，导致线程都不能正常执行完，从而产生了死锁。

 

死锁的例子：

 

public class TestDeadLock 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 (InterruptedException e) {
                    e.printStackTrace();
                }

                synchronized (o2){
                    System.out.println("1");
                }
            }
        }

        if (flag == 0){
            synchronized (o2){
                try {
                    Thread.sleep(500);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }

                synchronized (o1){
                    System.out.println("0");
                }
            }
        }
    }

    public static void main(String[] args) {
        TestDeadLock td1 = new TestDeadLock();
        TestDeadLock td2 = new TestDeadLock();
        td1.flag = 1;
        td2.flag = 0;

        Thread t1 = new Thread(td1);
        Thread t2 = new Thread(td2);

        t1.start();
        t2.start();

    }
}