class Test {
    public static void main(String[] args) {
        Cat cat = new Cat();
        Dog dog = new Dog();
        Thread td1 = new Thread(cat);
        Thread td2 = new Thread(dog);
        td1.start();
        td2.start();
        for (int i =0 ; i<3 ; i++){
            System.out.println("main thread");
        }
    }

}

public class Cat implements Runnable{


    @Override
    public void run() {
            for (int i =0 ; i<3 ; i++){
                System.out.println(Thread.currentThread().getName()+"A dog");
            }

    }
}

​public class Dog implements Runnable{



    @Override
    public void run() {
        for (int i =0 ; i<3 ; i++){
            System.out.println(Thread.currentThread().getName()+"A cat");
        }
    }
}