Java锁的活跃性

class BigRoom {
	private final Object studyRoom = new Object();
	private final Object bedRoom = new Object();
	
	public void sleep() {
		// synchronized (this) {
		synchronized (bedRoom) {
			log.debug("sleeping 2 小时");
			Sleeper.sleep(2);
		}
	}
	public void study() {
		// synchronized (this) {
		synchronized (studyRoom) {
			log.debug("study 1 小时");
			Sleeper.sleep(1);
		}
	}
}

Object A = new Object();
Object B = new Object();
 
Thread t1 = new Thread(() -> {
	synchronized (A) {
		log.debug("lock A");
		sleep(1);
		synchronized (B) {
			log.debug("lock B");
			log.debug("操作...");
		}
	}
}, "t1");
 
Thread t2 = new Thread(() -> {
	synchronized (B) {
		log.debug("lock B");
		sleep(0.5);
		synchronized (A) {
			log.debug("lock A");
			log.debug("操作...");
		}
	}
}, "t2");
 
t1.start();
t2.start();

static volatile int count = 10;  
static final Object lock = new Object();  
 
public static void main(String[] args) {  
    new Thread(() -> {  
        // 期望减到 0 退出循环  
        while (count > 0) {  
            sleep(0.2);  
            count--;  
            log.debug("count: {}", count);  
        }  
    }, "t1").start();  
    new Thread(() -> {  
        // 期望超过 20 退出循环  
        while (count < 20) {  
            sleep(0.2);  
            count++;  
            log.debug("count: {}", count);  
        }  
    }, "t2").start();  
}