Introducing OOP

In Chapter 1, The First App, we mentioned that Java was an object-oriented language. An object-oriented language requires us to use object-oriented programming.

Tip

My ten-year-old son has been especially helpful in devising a unique way of remembering OOP. He suggests simply reversing its letters. I will let the reader decide whether to use this particular memory jogger or one of his or her own.

Let's find out a little bit more.

What is OOP exactly?

OOP is a way of programming that involves breaking our requirements down into chunks that are more manageable than the whole.

Each chunk is self-contained yet potentially reusable by other programs, while working together as a whole with the other chunks.

These chunks are what we have been referring to as objects. When we plan/code an object, we do so with a class. A class can be thought of as the blueprint of an object.

We implement an object of a class. This is called an instance of a class. Think about a house blueprint. You can't...