Object Types

Quick Index

Now let's look at object type. This page is very important 💡.

Recall our set of nine persons (objects).

Can we generalize all of these into one general object type?

Person
😊
firstName

Let's define a simple object type for Person and give it one property:

firstName -- The first name of the specific person instance/object

Recall our collection of many balls (objects).

Can we generalize all of these into one general object type?

Let's define an object type for Ball and give it these properties:

Recall our collection of many rectangles (objects).

Can we generalize all of these into one general object type?

Let's define an object type for Rectangle and give it these properties:

Note that for real rectangle objects, "width" and "height" will vary. They are variables. We'll learn more about these later.

Here is another perspective.

We have one "Rectangle type" (properties width and height).

We have many rectangle objects.

Introduction To Objects With Java (Chapter 301 - Object Types and Objects)