Interface In JAVA & Multiple Inheritance

MULTIPLE INHERITANCE

Lets Understand what multiple inheritance is
Multiple inheritance is a feature of some object-oriented computer programming languages in which an object or class can inherit features from more than one parent object or parent class.

as shown in above figure in multiple inheritance child class can have 2 or more base class to achieve this we need INTERFACE.

INTERFACE

An interface in Java is a blueprint of a class. It has static constants and abstract methods. i.e. An Interface can only contain abstract methods() and variables, it cannot have body of a method. It cannot be instantiated just like the abstract class.

• So where do we declare the body of these methods??

  The body of method is declared inside a class where the method is needed according to the programmer's requirement.

• How to declare and interface?

  Interface is declared using interface keyword
  Syntax :
  interface interface_name{ abstract methods}

• Note

  To use declared interface in class we need to use implements keyword

Implementation

First we will create a interface "print" and inside it we will create a abstract method print();

interface printgib{
void print();
}

Now we got our interface ready to be used by classes so lets create classes abc and gk and implement interface in it.

public class abc implements printgib{
public void print(){                     //1st implementation of print 
System.out.println("I love you 3000"); 
}
public static void main(String[] args){
abc obj = new abc();
gk obj1 = new gk();
obj.print();
obj1.print();
}
}

class gk implements printgib{
public void print(){                   //2nd implementation of print 
System.out.println("I am Gk");
}
}

as shown in above code we achieved multiple inheritance and implemented interface.

• Now to run the code save the file and

  javac file_name.java
  

  java abc
  

Output:-

Code