Inheritance Introduction

In the Java language, classes can be derived from other classes, thereby inheriting fields and methods from those classes.
A class that is derived from another class is called a subclass (also a derived class, extended class, or child class). The class from which the subclass is derived is called a superclass (also a base class or a parent class).

Inheritance Basics

To inherit a class, you simply incorporate the definition of one class into another by using the extends keyword. Consider a single example :

class first {
	public void function1() {
		System.out.println("Inside Base Class");
	}
}

public class SimpleInheritance extends first { // extends is used to inherit
												// elements from first class to
												// second class
	/* function1() is also present here, but not visible */
	public void function2() {
		System.out.println("Inside Derived Class");
	}

	public static void main(String[] args) {
		SimpleInheritance object1 = new SimpleInheritance();
		object1.function1(); // calling base class function1
		object1.function2(); // calling present class function2
	}
}