Java中实现两个线程交替运行的方法

package com.java265.other;

public class Test6 {
    /*
     * 两个线程 一个线程输出 a b c d e f 一个线程输出 1 2 3 4 5 交叉输出 a 1 b 2 c 3
     */
    static boolean flag = false;
    public static void main(String[] args) {

        Object o = new Object();



        Thread t1, t2;

        t1 = new Thread(() -> {
            for (int i = 0; i < 26; ) {
                synchronized (o) {
                    if (!flag) {
                        char t = (char) (i + (int) 'a');
                        System.out.print(t);
                        i++;
                    try {
                            o.wait();
                        } catch (InterruptedException e) {
                        e.printStackTrace();
                        }
                        flag = false;
                        o.notifyAll();

                    }

                }

            }


        });

        t2 = new Thread(() -> {
            for (int i = 1; i <= 26;) {
                synchronized (o) {

                    if (flag) {
                        System.out.print(i);
                        i++;
                    try {
                            o.wait();
                    } catch (InterruptedException e) { 
                        e.printStackTrace();
                    }
                    }

                    flag = true;
                    o.notifyAll();
                }
            }

        });

        t1.start();
        t2.start();

    }
}