What is the benefit using different type when creating an object in java

Asked Feb 20 '18 at 11:22

Active Feb 20 '18 at 11:22

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What is the benefit using different type when creating an object in java?

If i have 2 classes:

public class Animal {

    public Animal() {
    }

    public void move() {
        System.out.println("Moving...");
    }
}


public class Bird extends Animal {

    public Bird() {
    }

    public void fly() {
        System.out.println("Flying...");
    }
}

When i should use:

Animal bird1 = new Bird();

and

Bird bird2 = new Bird();

I still can not understand if Bird extends Animal, why using Animal as variable type?

asked Feb 20 '18 at 11:22

J. Doem

1

When `bird1` will be used in a context where you don't care whether it's a `Bird` or a `Reptile` – Federico klez Culloca Feb 20 '18 at 11:24
1

J. Doem this is the same like asking:" why build a foundation when you build a house". In Animal you put everything that is shared among all types of Animals, the specifications for each type of Animal, you put in the subclasses. – Stultuske Feb 20 '18 at 11:24
1

Not quite a duplicate, but definitely related: https://stackoverflow.com/questions/383947 – Jon Skeet Feb 20 '18 at 11:24
1

Well there could be use case where you iterate through a list of Animals and call the move method on the returned object. – Nelson Christos Feb 20 '18 at 11:29
1

It is related to concept of dynamic polymorphism or method overriding in oop. – Jay Shankar Gupta Feb 20 '18 at 11:29

What is the benefit using different type when creating an object in java

0 Answers0