yield实现线程交替运行

yield的意思是放手，放弃，一个线程调用yield意味着它要告诉虚拟机自己乐意让其它线程占用自己的位置。

class Producer extends Thread
{
    public void run()
    {
        for(int i = 0; i < 5; i++)
        {
            System.out.println("i am producer: producerd item " + i);
            Thread.yield();
        }
    }
}  

class Consumer extends Thread
{
    public void run()
    {
        for(int i = 0; i < 5; i++)
        {
            System.out.println("i am Consumer: Consumed item " + i);
            Thread.yield();
        }
    }
}
public class JoinAndYieldTestDemo
{  

    /**
     * @param args
     */
    public static void main(String[] args)
    {  

        Thread producer = new Producer();
        Thread consumer = new Consumer();  

        producer.setPriority(Thread.MIN_PRIORITY);
        consumer.setPriority(Thread.MAX_PRIORITY);  

        producer.start();
        consumer.start();
    }  

}