java7开始io就有try-with-resource。
可以利用这一个特性，来说实现，自动释放。
代码如下：

public class AutoUnlockProxy implements Closeable {

    private Lock lock;

    public AutoUnlockProxy(Lock lock) {
        this.lock = lock;
    }

    @Override
    public void close() throws IOException {
        lock.unlock();
        System.out.println("释放锁");
    }

    public void lock() {
        lock.lock();
    }

    public void tryLock(long time, TimeUnit unit) throws InterruptedException {
        lock.tryLock(time, unit);
    }

    public static void main(String[] args) {

        try (AutoUnlockProxy autoUnlockProxy = new AutoUnlockProxy(new ReentrantLock())) {
            autoUnlockProxy.lock();
            System.out.println("加锁了");
        } catch (IOException e) {
            e.printStackTrace();
        }

    }

}