public class Dog {
    private float height;
    private float weight;
    
    public Dog(float height, float weight) {
        this.height = height;
        this.weight = weight;
    }
    
    public void walk() {
        //walking
    }

}

public class BullDog extends Dog {
    public void walk() {
        //bulldog walking
    }
} 

public class ChihuahuaDog extends Dog {
    public void walk() {
        //chihuahua walking
    }
}