Java Inheritance — Free Java Tutorial

TL;DR: Learn Java Inheritance in Java with a free, beginner-friendly tutorial, examples and practice for Indian students on Syllab.in.

Java Inheritance in Java

Inheritance allows a class (child/subclass) to acquire the fields and methods of another class (parent/superclass). Use the `extends` keyword.

Polymorphism means "many forms" — a parent type reference can hold a child type object. The correct method is called at runtime based on the actual object type (dynamic dispatch).

The `super` keyword refers to the parent class. Use `super()` to call the parent constructor; use `super.method()` to call a parent method from the child.

Method overriding: a child class provides its own implementation of a method defined in the parent. Use `@Override` annotation to signal this intent.

Abstract classes (declared with `abstract`) cannot be instantiated directly. They serve as base classes and can have abstract methods (no body) that subclasses must implement.

Interfaces define a contract — a set of method signatures that implementing classes must provide. A class can implement multiple interfaces (unlike extends, which allows only one parent).

// Parent class
public class Animal {
    protected String name;
    public Animal(String name) { this.name = name; }
    public void speak() { System.out.println("..."); }
}

// Child class
public class Dog extends Animal {
    public Dog(String name) { super(name); }  // call parent constructor

 

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