Java多线程：用三个线程控制循环输出10次ABC

import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

public class PrintABC {
    public static int cnt = 0;
    public static final int COUNT = 30;
    public static void main(String[] args) {
        
        final Lock lock = new ReentrantLock();
        Thread A = new Thread(new Runnable(){

            @Override
            public void run() {
                while(true){
                    lock.lock();
                    if(cnt>=COUNT){
                        lock.unlock();
                        return;
                    }
                    if(cnt%3==0){
                        System.out.println("A");
                        cnt++;
                    }
                    lock.unlock();
                }                
            }
            
        });

        Thread B = new Thread(new Runnable(){
            public void run(){
                while(true){
                    lock.lock();
                    if(cnt>=COUNT){
                        lock.unlock();
                        return;
                    }
                    if(cnt%3==1){
                        System.out.println("B");
                        cnt++;
                    }
                    lock.unlock();
                }
            }
        });
        
        Thread C = new Thread(new Runnable(){
            public void run(){
                while(true){
                    lock.lock();
                    if(cnt>=COUNT){
                        lock.unlock();
                        return;
                    }
                    if(cnt%3==2){
                        System.out.println("C");
                        cnt++;
                    }
                    lock.unlock();
                }
            }
        });
        A.start();
        B.start();
        C.start();
    }

}

A
B
C
A
B
C
A
B
C
A
B
C
A
B
C
A
B
C
A
B
C
A
B
C
A
B
C
A
B
C