借助wait和notify方法控制线程以固定的顺序执行： 

 /*** 控制输出字符的顺序，必须是固定顺序2,1* 采用wait-notify实现* @param args*/public static void main(String[] args) {new Thread(() -> {synchronized (lock) {while (!isPrint2) {try {lock.wait();} catch (InterruptedException e) {e.printStackTrace();}}log.info("1");}}, "t1").start();new Thread(() -> {synchronized (lock) {log.info("2");isPrint2 = true;lock.notify();}}, "t2").start();}
}

借助park和unpark方法控制线程以固定的顺序执行： 

@Slf4j
public class ParkOrderDemo {public static void main(String[] args) {Thread t1 = new Thread(() -> {LockSupport.park();log.info("1");}, "t1");t1.start();new Thread(() -> {log.info("2");LockSupport.unpark(t1);}, "t2").start();}
}