防止java主线程退出

如果是web项目，会启动端口监听，主线程阻塞不会退出。但如果是普通的java项目对外提供服务，主线程一旦跑完，整个进程就退出了。
之前见过有使用死循环方式来防止退出的。着实捏了把冷汗，这会导致cpu占用变高。那有没有更优雅的方式呢，我从阿里开源RPC框架dubbo中找到了答案

public class StartMain {
    
    private static final ReentrantLock LOCK = new ReentrantLock();
    private static final Condition STOP = LOCK.newCondition();
  
    public static void main(String[] args) {


        AbstractApplicationContext applicationContext = new ClassPathXmlApplicationContext("applicationContext.xml");
        applicationContext.start();
        logger.info("service start success !~");
        addHook(applicationContext);
        //主线程阻塞等待，守护线程释放锁后退出
        try {
            LOCK.lock();
            STOP.await();
        } catch (InterruptedException e) {
            logger.warn(" service   stopped, interrupted by other thread!", e);
        } finally {
            LOCK.unlock();
        }

    }

    /**
     * Created on 2017年12月12日
     * <p>
     * Discription:[添加一个守护线程]
     *
     * @param applicationContext
     * 
     */
    private static void addHook(AbstractApplicationContext applicationContext) {
        Runtime.getRuntime().addShutdownHook(new Thread(() -> {

            try {
               
                applicationContext.stop();
            } catch (Exception e) {
                logger.error("StartMain stop exception ", e);
            }

            logger.info("jvm exit, all service stopped.");
            try {
                LOCK.lock();
                STOP.signal();
            } finally {
                LOCK.unlock();
            }
        }, "StartMain-shutdown-hook"));
    }

}