public class Bird {

    // for most birds this is OK, they fly
    public String getMovement() {
        return "Fly";
    }

    public String getCover() {
        return "Feathers";
    }

}


public class Penguin extends Bird {

    // penguins don't fly, so we need to override the parent method in order to create more realistic penguins
    @Override
    public String getMovement() {
        return "Walk";
    }
    //we don't override getCover because penguins do have "Feather"
}