JAVA多线程的笔试题

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

public class Main {
    ReentrantLock lock = new ReentrantLock();
    Condition c1 = lock.newCondition();
    Condition c2 = lock.newCondition();
    Condition c3 = lock.newCondition();
    int num = 1;
    public static void main(String[] args) {
        Main main = new Main();
        new Thread(()->{
            for (int i = 0; i < 10; i++) {
                main.printA();
            }
        }).start();
        new Thread(()->{
            for (int i = 0; i < 10; i++) {
                main.printB();
            }
        }).start();
        new Thread(()->{
            for (int i = 0; i < 10; i++) {
                main.printC();

            }
        }).start();

    }
    public void printA(){
        lock.lock();
        try {
            while (num != 1){
                c1.await();
            }
            System.out.print("A");
            num = 2;
            c2.signal();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }finally {
            lock.unlock();
        }
    }
    public void printB(){
        lock.lock();
        try {
            while (num != 2){
                c2.await();
            }
            System.out.print("B");
            num = 3;
            c3.signal();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }finally {
            lock.unlock();
        }
    }
    public void printC(){
        lock.lock();
        try {
            while (num != 3){
                c3.await();
            }
            System.out.println("C");
            num = 1;
            c1.signal();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }finally {
            lock.unlock();
        }
    }

}