oop.md

OOP

Concepts

1. Abstraction implemented as Interfaces and Abstract classes
2. Incapsulation - public, protected, private
3. Inheritance - extends
4. Polymorphism - @Override

Inner / Nested Classes

public class Outer {
    class Inner {
        Inner() { System.out.println("Inner"); }
    }
    static class Nested {
        Nested() { System.out.println("Nested"); }
    }
}

public class Test {
    public static void main(String[] args) {
        Outer outer = new Outer();
        Outer.Inner inner = outer.new Inner();
        Outer.Nested nested = new Outer.Nested();
    }
}