【鎖】求解：關於lock.unlock以後 第二個線程沒法得到鎖的問題

代碼以下：

public class SynchronizedAndLockDemo {

    public static void main(String[] args) throws InterruptedException {

        Writer writer = new Writer();

        Thread t1 = new Thread(() -> {
            writer.testTryLock();

        });
        t1.setName("t1");

        Thread t2 = new Thread(() -> {
            writer.testTryLock();
        });
        t2.setName("t2");


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

    }

}


class Writer {

    Lock lock = new ReentrantLock();

    public void testTryLock() {
        String threadName = Thread.currentThread().getName();

        System.out.println(threadName + ":" + lock.tryLock());

        try {
            if (lock.tryLock(5000, TimeUnit.MILLISECONDS)) {
                lock.lock();
                System.out.println(threadName + " get the lock ...");
//                Thread.sleep(2000);
//                System.out.println(threadName + " sleep 2s");
            } else {
                System.out.println(threadName + " can't get the lock ...");
            }


        } catch (Exception e) {
        } finally {
            if (lock.tryLock()) {
                lock.unlock();
                System.out.println(threadName + " unlock");
            }
        }
    }
}

執行結果以下：

t1:true
t2:false
t1 get the lock ...
t1 unlock
t2 can't get the lock ...

按理說，t1釋放鎖後 t2是在5秒內獲取不到鎖才終止，可是t1在5s內已經完成了任務，而且釋放了鎖，爲何t2仍然沒法得到鎖呢？是t1還沒有釋放鎖嗎？那lock.unlock()方法是未生效的嗎？百思不得其解
跪求大佬解惑