This document summarizes a presentation on inheritance of interfaces in Java. It defines an interface as a blueprint of a class that contains abstract methods. Interfaces allow classes to support multiple inheritance by implementing multiple interfaces. The document provides the syntax for declaring an interface and explains that a class implements an interface while a class extends another class. It gives an example of a Drawable interface being implemented by Rectangle and Circle classes. Finally, it demonstrates multiple inheritance using interfaces by defining a Printable and Showable interface both being implemented by class A7.

1. B.TECH COMPUTER SCIENCE AND ENGINEERING [AI-ML]
YEAR : 2nd
SEMESTER : 4th
SUBJECT : FORMAL LANGUAGE AND AUTOMATA THEORY
SUBJECT CODE : PCC-CSM404
Presentation Topic: Inheritance of interface in java
SUBMITED TO :
KAUSTAV ROY
BRAINWARE UNIVERSITY
Department Of Computer Science And Engineering - Presented by SOHAM MATHUR
BWU/BTA/21/130

2. What is an interface
• An interface in java is a blueprint of a class. It has static constants and
abstract methods.
• The interface in java is a mechanism to achieve abstraction.
• It is used to achieve abstraction and multiple inheritance in java.

3. Why use Java interface
• It is used to achieve abstraction.
• By interface, we can support the functionality of multiple inheritance.
• It can be used to achieve loose coupling.

4. How to Declare an interface
• An interface is declared by using the interface keyword.
• All the methods in an interface are declared with the empty body, and
all the fields are public, static and final by default.
• A class that implements an interface must implement all the methods
declared in the interface.

5. Syntax
interface<interface_name>
{
//declare constant fields
//declare methods that abstract
//by default
}

6. The relationship between classes and
interfaces
• As shown in the figure given below, a class extends another class, an
interface extends another interface, but a class implements an
interface.
Class interface interface
extends implements extends
Class Class interface

7. Java Interface Example
{
void draw();
}
//Implementation: by second user class
Rectangle implements drawable
{
public void draw()
{
System.out.println(“drawing rectangle”);
}
}
Class Circle implements Drawable
{
public void draw()
{
System.out.println(“drawing circle”);
}
}
//using interface: by third user public class interface
{
public static void main(String args[])
{
Drawable d=new Circle(); //In real scenario, object
is provided by method e.g.
get Drawable()
Drawable r=new Rectangle();
d.draw();
r.draw();
}
}
//Interface declaration: by first user interface Drawable

8. Multiple inheritance in Java by interface
• If a class implements multiple interfaces, or an interface extends multiple
interfaces, it is known as multiple inheritance.
Interface Interface interface interface
implements extends
class interface

9. Multiple inheritance using interface
Interface printable
{
void print();
}
Interface showable
{
Void show();
}
Public class A7 implements printable, showable
{
public void print()
{
System.out.println(“Hello”)
}
public void show()
{
System.out.println(“Welcome”);
}
public static void main(String args[])
{
A7 obj = new A7();
obj.print();
obj.show();
}
}