The Class Point

Think of a two dimensional point as an object that consists of two values, the distance x from the origin along a horizontal axis, and the distance y from the origin along a vertical axis:

It is convenient to think of a point as a single "thing" (not as two separate things.) For example, you think of the end point of a line as one thing. And you thing of the corner of a square as one thing. This is an example of abstraction. In Java, an abstraction usually calls for a class.

Java comes with a library of predefined classes that are used for building graphical user interfaces. This library is called the Application Windowing Toolkit, or the AWT. One of the many classes defined in this library is the class Point. A class (remember) is a description of a possible object. A class library is a collection of plans that your program might use when it creates objects.

The class Point describes two things: the variables (the data) and the methods (the behavior) of Point objects.