public class JoinTest {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Thread t1 = new ThreadA();//利用多态实例化一个A线程
		Thread t2 = new ThreadB(t1);//利用多态实例化一个B线程
		t1.start();
		t2.start();
	}

}

/*继承于Thread的子类*/
class ThreadA extends Thread {
	public void run() {
		for (int i = 1; i <= 20; i++) {
			System.out.println(i + "  ￥￥￥");
			try {
				Thread.sleep(1000);
			} catch (InterruptedException e) {
			}
		}
	}
}

/*继承于Thread的子类*/
class ThreadB extends Thread {
	private Thread t;

	public ThreadB() {
	}

	public ThreadB(Thread t) {
		this.t = t;
	}

	public void run() {
		for (int i = 1; i <= 20; i++) {
			System.out.println(i + "  ###");
			try {
				Thread.sleep(1000);
				if (i == 10) {
					t.join();// join 使这两个线程进入串行状态（也就是说t突然插了进来，必须等t执行完毕之后，才会让B线程继续执行）
				}
			} catch (InterruptedException e) {
			}
		}
	}
}