= 2021-09-22 =

* http://www.plantuml.com/plantuml/png/SoWkIImgAStDuKfCAYufIamkKO02nxpCtCGShioyajIYjCJaLAYmStvEVX66g7jgNafg4HT4Zu9DZQukPq1cEWhV9H-LxvnOmWLK0zGCLvzUoUMI3nS16mpa0qM1Qb54lJDBIbBpkC1k0GdhwO65GKP2N88gvW0K0teH0000
{{{
@startuml
abstract        Animal
interface       Color
interface       Gender
Animal <|--	Pig
Animal <|--	Dog
Animal <|--	Cat
Pig    <|--	Piggy
Dog    <|--     Doggy
Cat    <|--     Kitten
Color  <|..     Cat
Gender <|..     Cat
@enduml
}}}

- [[Image(OOP_Concepts.png)]]

{{{
#!java
public class HelloWorld{

     public static void main(String []args){
        System.out.println("Hello World");
        
        Animal a = new Cat();
        Animal b = new Kitten();
        
        a.who_am_i();
        b.who_am_i();
     }
}

abstract class Animal {
    abstract void who_am_i();
}

class Cat extends Animal {
    void who_am_i() {
        System.out.println("I'm a Cat");
    }
}

class Kitten extends Cat {
    void who_am_i() {
        System.out.println("I'm a Kitten");
    }
}
}}}