实现Runnable，轻松实现多线程间的资源共享

 public class Test {

    class TestRunnable implements Runnable {

        private String TName="TName";

        private Object obj=new Object();

        private int a=5;

        public void run() {

            synchronized (obj) {

                a--;

                if (a <= 0) {
                    System.out.println(TName + " notifyALL:" + a);
                    obj.notifyAll();
                } else {
                    System.out.println(TName + " wait:" + a);
                    try {
                        obj.wait();
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            }


            System.out.println(TName + " relese :" + a);
        }
    }

    public static void main (String[] args){

        System.out.println("hello word");

        Test t=new Test();
        Runnable run_a=t.new TestRunnable();

        for(int i=0; i<5;i++){
            new Thread(run_a).start();
        }

    }
}

// wait是让使用wait方法的对象等待，暂时先把对象锁给让出来，给其它持有该锁的对象用，其它对象用完后再告知（notify）等待的那个对象可以继续执//  行了，整个过程就是这样