public class Main {
public static void main(String[] args) {
       ThreadA threadA = new ThreadA();
       ThreadB threadB = new ThreadB();

       threadA.start();
       threadB.start();

try {
           Thread.sleep(3000);
       } catch (InterruptedException e) { }
       threadA.work = false;

try {
            Thread.sleep(3000);
        } catch (InterruptedException e) { }
        threadA.work = true;

try {
            Thread.sleep(3000);
        } catch (InterruptedException e) { }
        threadA.stop = true;
        threadB.stop = true;

    }
}

class ThreadA extends Thread {
public boolean stop = false;
public boolean work = true;

@Override
    public void run() {
while (!stop) {
if (work) {
                System.out.println("ThreadA 작업 내용");
            } else  {
                Thread.yield();
                System.out.println("yield() A 호출");
            }
        }
        System.out.println("ThreadA 종료");
    }
}

class ThreadB extends Thread {
public boolean stop = false;
public boolean work = true;

@Override
    public void run() {
while (!stop) {
if (work) {
                System.out.println("ThreadB 작업 내용");
            } else  {
                Thread.yield();
                System.out.println("yield() B 호출");
            }
        }
        System.out.println("ThreadB 종료");
    }
}