This document discusses abstract classes and interfaces in object-oriented programming. It explains that abstract classes can have both abstract and concrete methods while interfaces contain only abstract methods. The document also demonstrates polymorphism through an abstract calculateSalary() method that is implemented differently in subclasses. It concludes by reviewing inheritance relationships and the pillars of OOP - encapsulation, inheritance, and polymorphism.

1. Day 4

2. Abstract Class

3. animal

4. mammal

5. abstract methods

6. Abstract Class Vs Interface

7. AC - Stereotype I - Behavior

8. AC - single I - multiple

9. Polymorphism

10. Employee abstract calculateSalary() Stylist Administrator calculateSalary() calculateSalary() ArtMaster calculateSalary()

11. for (Employee e : employees) { System.out.println(e.getName() + “salary: “ + e.calculateSalary()); }

12. One more thing about inheritance

13. IS - A

14. HAS - A

15. Black Coffee Black Coffee with sugar Espresso Cappuccino Mochaccino

16. Encapsulation Inheritance Polymorphism