Sams Teach Yourself Object Oriented Programming in 21 Days, Second Edition

Chapter 7. Polymorphism: Time to Write Some Code

Yesterday you learned about polymorphism. You should have a good understanding of the four different types of polymorphism. Today you will gain hands-on experience with polymorphism through a number of lab exercises. By the end of today’s lesson, you should feel a bit more comfortable with the theory presented in Day 6, “Polymorphism: Learning to Predict the Future.”

Today you will learn

• How to apply the different forms of polymorphism

• How to write future proof software

• How polymorphism can help you avoid switch logic

Lab 1: Applying Polymorphism

In Day 5, Lab 2 introduced you to an employee hierarchy. Listing 7.1 presents a slightly altered Employee base class.

Example 7.1. Employee.java

public abstract ...