死锁，活锁例子

//死锁实例：

@AllArgsConstructor
@Data
class MyRunnable implements Runnable{
    private String lockA;
    private String lockB;


    @Override
    public void run() {
        synchronized (lockA){
            try {
                Thread.sleep(2000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            System.out.println("获得锁"+lockA+"，尝试获取"+lockB);
            synchronized (lockB){
                System.out.println("已经尝试获得锁"+lockB);
            }
        }
    }
}

    public static void main(String[] args) {
        String lockA = "lockA";
        String lockB = "lockB";
        new Thread(new MyRunnable(lockA,lockB)).start();
        new Thread(new MyRunnable(lockB,lockA)).start();
    }

活锁

    /**
     * 活锁
     * @param args
     * @throws InterruptedException
     */
    public static void main(String[] args) throws InterruptedException {
        ReentrantLock A = new ReentrantLock();
        ReentrantLock B = new ReentrantLock();
        new Thread(() -> {
            boolean noOkflag = true;
            while (noOkflag) {
                if (A.tryLock()){
                    System.out.println(Thread.currentThread()+"成功获取锁A");
                }
                if (B.tryLock()) {
                    System.out.println(Thread.currentThread()+"====================成功获取锁B");
                    B.unlock();
                    noOkflag = false;
                }
                if (A.isLocked()) {
                    A.unlock();
                }
            }
        }).start();

        new Thread(() -> {
            boolean noOkflag = true;
            while (noOkflag) {
                if (B.tryLock()) {
                    System.out.println(Thread.currentThread() + "成功获取锁B");
                }
                if (A.tryLock()) {
                    System.out.println(Thread.currentThread() + "=====================成功获取锁A");
                    A.unlock();
                    noOkflag = false;
                }
                if (B.isLocked()) {
                    B.unlock();
                }
            }
        }).start();
    }