Superclass with no 'no-arg' constructor

[John Paterson]

Hi Folks...


How do I code the constructor for the subclass when I have a superclass which does not have a 'no-arg' constructor and I am not at liberty to insert one into it. Do have a look at the following code:

Animal

class Animal {

    Animal(String name) {
    }
    
}

Horse

class Horse extends Animal {

    
    Horse() {
        
    }
}

As it is there is compiler error due to the fact that there is no 'no-arg' constuctor in the super class. Hope someone can advise. Thanks.

regards
John

[gurpeet singh]

the horse constructor that you have supplied is a no-arg constructor. now the first line in any constructor will be a call to super or this. if you don't explicitly insert this or super call compiler will insert its no-arg super call which is like this super(). so when you wrote your horse constructor internally it will look like this

Horse()
{
super();              // compiler error because there is no no-arg constructor in superclass Animal

}

so in this case you have to explicitly insert super call which takes string parameter like this

Horse()
{
super("<Some string name>")
}

[camilo lopes]

if you created a constructor in superclass without args, you cannot call super() in subclass, because the default constructor is not created when we create a constructor with args. If you want to do of that code work, so add a constructor no args in superclass, like this:

Animal(){}

[gurpeet singh]

camilo lopes wrote:if you created a constructor in superclass without args, you cannot call super() in subclass, because the default constructor is not created when we create a constructor with args. If you want to do of that code work, so add a constructor no args in superclass, like this:

Animal(){}

hi camilo. the original question says that "you don't have the liberty to insert no-arg constructor to Animal class" so you cannot modify Animal class. you have to insert super call with a string argument.

[camilo lopes]

gurpeet singh wrote:

camilo lopes wrote:if you created a constructor in superclass without args, you cannot call super() in subclass, because the default constructor is not created when we create a constructor with args. If you want to do of that code work, so add a constructor no args in superclass, like this:

Animal(){}

hi camilo. the original question says that "you don't have the liberty to insert no-arg constructor to Animal class" so you cannot modify Animal class. you have to insert super call with a string argument.

oh yeah. I had forgotten of this part. thanks for remember me :0.

[John Paterson]

Hi Guys..

Thanks for the replies. Gurpeet Singh, your suggestion works. Thanks once again.

regards
John

[gurpeet singh]

welcome