多线程交替打印数字和字母

数字从1打印到52， 字母从A打印到Z
例如 12A34B·······

package 酷家乐0913;
public class A {
    static class Thread1 implements Runnable{
        private  int num = 1;
        private int step = 1;
        private  char c = 'A';
        @Override
        public void run() {
            synchronized (this){ // 核心的地方，需要把这个类锁住
                while (step<=78){
                    this.notify(); // 通知需要这个类的线程，开始竞争锁。
                    if(step%3 ==0){
                        System.out.print(c++);
                        step++;
                    }else {
                        System.out.print(num++);
                        step++;
                    }
                    try {
                        Thread.sleep(1);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                    try {
                        this.wait();//释放锁
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            }
        }
    }
    public static void main(String[] args) {
        Thread1 t1 = new Thread1();
        new Thread(t1).start();
        new Thread(t1).start();
    }
}