Java Interface

Interface

What is interface:

• Interface is similar to class.it is a collection of abstract method.

• Interface dont have defination.

• A class can implements an interface.thereby inheriting a abstract methods of the interface.

• Abstract methods an interface also contain constants,and default methods,static methods.

• Method body exits only for default methods and static methods.

• Interface can have any number of methods.

• You cant create object for interface.

• Interface dont not have constractor.

• An interface can extend multiple interfaces.

Declaring Interfaces: 

• The interface keyword is used to declare an interface.

  Example:

  public interface SampleInterface{

}

properties for interface:

• An interface is a implictily abstract menthod so you no need to declare abstract keyword.

• Methods in an interface are implicitily public.

Example:

interface Animal{

public void eat();

public void travel();

}

Implemeting Interface:

• A class uses the implements keyword to implement an interface. The implements keyword appears in the class declaration following the extends portion of the declaration.

Example:

public class Mammal implements Animal{

public void eat(){

System.out.println("Mammal can eat");

}
public void travel(){

System.out.println("Mammal can travel");

}
public int noOfLegs(){

return 0;

}

Public static void main(String args[]){

Mammal mam=new Mammal();

mam.eat();

mam.travel();

}

}

Result:

Mammal can eat.
Mammal can travel.

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