Help with constructors using inheritance

Question

hi,
i am having trouble with contructors in inheritance.
i have a class Seahorse extends Move extends Animal
in animal class , i have this constructor .
public class Animal() {
public Animal (char print, int maxage, int speed) {
this.print = print;
this.maxage = maxage;
this.speed = speed;
public class Move extends Animal {
public Move(char print, int maxage, int speed)
super(print, maxage, speed); //do i even need this here? if i dont i
//get an error in Seahorse class saying super() not found
public class Seahorse extends Move {
public Seahorse(char print, int maxage, int speed)
super('H',10,0);
please help

Answer 1

It's not a problem, it's how Java works. First, if you do not create a constructor in your code, the compiler will generate a default constructor that does not take any arguments. If you do create one or more constructors, the only way to construct an object instance of the class is to use one of the constructors.
Second, when you extend a class, your are saying the subclass "is a" implementation of the super class. In your case, you are saying Move is an Animal, and Seahorse is a Move (and an Animal as well). This does not seem like a good logical design, but that's a different problem.
Since you specified that an Animal can only be constructed by passing a char, int, and int, that means that a Move can only be constructed by calling the super class constructor and passing a char, int, and int. Since Move can only be constructed using a char, int and int, Seahorse can only be constructed by calling super(char, int, int);.
It is possible for a subclass to have a constructor that does not take the same parameters as the super class, but the subclass must call the super class constructor with the correct arguments. For example, you could have.
public Seahorse() {
   super('S',2,5);
}The other problem is, Move does not sound like a class. It sounds like a method. Perhaps you might have MobileAnimal, but that would only make sense if there was a corresponding StationaryAnimal. Your classes should model your problem. It's hard to image a problem in which a Seahorse is a Move, and a Move is an Animal. It makes more sense for Animals to be able to move(), which allows a Seahorse to move differently compared to an Octopus.