Java Inheritance & Polymorphism

extends, super and overriding.

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Inheritance: class Dog extends Animal gets Animal's fields and methods.
super calls the parent's constructor or methods.
@Override marks a method that replaces a parent method.
Polymorphism: a parent-type variable can hold any child object, and the child's version of the method runs.
final classes cannot be extended.

Key Takeaways: Java Inheritance & Polymorphism

Mastering Java Inheritance & Polymorphism helps you write clean and reliable Java code. Follow standard conventions, test edge cases, and keep logic simple. Try running the code example below and complete the exercises to build confidence.

Java Inheritance & Polymorphism Code Example

Java

class Animal {
    String name;
    Animal(String name) { this.name = name; }
    String sound() { return "..."; }
}

class Dog extends Animal {
    Dog(String name) { super(name); }
    @Override String sound() { return "Woof"; }
}

class Cat extends Animal {
    Cat(String name) { super(name); }
    @Override String sound() { return "Meow"; }
}

public class Main {
    public static void main(String[] args) {
        Animal[] pets = {new Dog("Moti"), new Cat("Billo")};
        for (Animal a : pets) {
            System.out.println(a.name + " says " + a.sound());
        }
    }
}

Output