Inheritance


Tuesday, December 5, 2023

Inheritance in Java is one of the fundamental pillars of Object-Oriented Programming (OOP). It provides a mechanism through which a class can inherit properties and behaviors from another class.

Class Hierarchy

In inheritance, classes are organized in a hierarchy, where a more specific class (subclass or child class) inherits characteristics from a more general class (superclass or parent class). For example, if you have a class "Animal" as a superclass, you could have subclasses like "Dog" and "Cat."

Inheritance models the "is-a" relationship. If a class B inherits from a class A, it can be said that B is a type of A. A Dog is a type of Animal.

In Java, inheritance is implemented using the extends keyword. When you define a child class, you use extends to indicate from which class it is inheriting.

public class Dog extends Animal {
    // code of the Dog class
}

The subclass inherits both methods and attributes from the superclass. This means it can use and, in some cases, modify the behavior defined in the superclass.

public class Animal {
    public void eat() {
        System.out.println("The animal eats.");
    }
}

public class Dog extends Animal {
    // The Dog class inherits the eat method from the Animal class
}

Inherited members (methods and attributes) can be used directly in the subclass. Visibility depends on access modifiers (public, private, protected).

public class Dog extends Animal {
    public void bark() {
        System.out.println("Woof, woof!");
    }

    public void performActivity() {
        eat(); // Access to the inherited method from the superclass
        bark(); // Subclass's own method
    }
}

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