Interface in JAVA

Author posted by Jitendra on Posted on under category Categories JAVA and tagged as Tags with 2 Comments on Interface in JAVA

Explains the usage and benefits of interface in JAVA.

Interface & Its Advantage:-

1. If all the methods in the class is abstract then the class is nothing but the interface.

2. We cannot create an object of interface.

3. To implement the interface by child class keyword “implements” is used.

4. Interface is defined by using keyword interface.

5. If a class implements interface but does not implements methods, then the class is abstract class.

6. We can assign the object of class which implements the interface of type of                                                     that interface.

interface Duck
{
    Void DuckType();
    Void DuckProperty();
}

class BlackDuck implements Duck
{
 Public void DuckType()
 {
     System.out.println("Black Duck");
 }

 Public void DuckProperty()
 {
   System.out.println("Swim, Quack  and Fly");
 }
 }

class TestDuck
{
 Public static void main(String args[])
 {
     BlackDuck obj=new BlackDuck();
     Obj.DuckType();
     Obj.DuckProperty();
 }
}

Advantages of Interface:-

  • Runtime Polymorphism
  • Contract can be used throughout the application

To know more about inheritance and abstract classes, refer this article.

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2 thoughts on “Interface in JAVA”

  1. My problem with descriptions of interfaces is that you can create the child classes and define the methods without using an interface. Since the child class is being instantiated anyway, what is the point of creating an interface? If you need to change the base interface, you’d need to change the children anyway, so I still don’t see the advantage in the examples presented.

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