009 wait notify等方法

private static Object lock = new Object();
    private static int index = 1;
    private static volatile Boolean flag = true;

    /**
     * 生产者的线程
     */
    static class Provider {

        public static void proIndex() {
            synchronized (lock) {
                if (!flag) {
                    System.out.println(Thread.currentThread().getName() + "--" + index++);
                    lock.notify();
                    flag = !flag;
                } else {
                    try {
                        lock.wait();
                    } catch (InterruptedException e1) {
                        e1.printStackTrace();
                    }
                }

            }
        }
    }

    /**
     * 消费者的线程
     */
    static class Consumer {

        public static void conIndex() {
            synchronized (lock) {
                if (flag) {
                    System.out.println(Thread.currentThread().getName() + "--" + index);
                    lock.notify();
                    flag = !flag;
                } else {
                    try {
                        lock.wait();
                    } catch (InterruptedException e1) {
                        e1.printStackTrace();
                    }
                }
            }
        }
    }

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

        new Thread(() -> {
            while (true) {
                sleep();    
                Provider.proIndex();
            }
        }).start();
        new Thread(() -> {
            while (true) {
                sleep();
                Consumer.conIndex();
            }
        }).start();
    }
    
    private static void sleep() {
        try {
            TimeUnit.SECONDS.sleep(1);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }