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What is Is-a relationship in Java?
IS-A is a way of saying: This object is a type of that object. Let us see how the extends keyword is used to achieve inheritance.
Example
public class Animal {
}
public class Mammal extends Animal {
}
public class Reptile extends Animal {
}
public class Dog extends Mammal {
}Now, based on the above example, in Object-Oriented terms, the following are true −
- Animal is the superclass of Mammal class.
- Animal is the superclass of Reptile class.
- Mammal and Reptile are subclasses of Animal class.
- Dog is the subclass of both Mammal and Animal classes.
Example
class Animal {
}
class Mammal extends Animal {
}
class Reptile extends Animal {
}
public class Dog extends Mammal {
public static void main(String args[]) {
Animal a = new Animal();
Mammal m = new Mammal();
Dog d = new Dog();
System.out.println(m instanceof Animal);
System.out.println(d instanceof Mammal);
System.out.println(d instanceof Animal);
}
}Output
true true true
Updated on: 30-Jul-2019
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