public class Program

{

	public static void main(String[] args) {

		healthy a = new healthy();

		healthy b = new unhealthy();

		a.food();

		b.food();

	}

}

class healthy{

    public void food(){

        System.out.println("vegetable");

    }

}

class unhealthy extends healthy{

    public void food(){

        System.out.println("meat");

    }

}

No, in your case create an interface or an abstract class if you want specific classes having a set instruction for methods.

I’m pretty sure if you want to create a new class you have to close the other close with Insert class name (here).close();