In our day-to-day life, we deal with a number of different objects. Some of these objects talk to us, some move on the road, and some fly in the sky. We naturally observe everything about the characteristics and behaviors of these objects. As an example, let's think about an object with the following properties: it has a couple of doors, four wheels, one steering wheel, brakes, gears, and an engine, it moves on the road, stops when the brakes are applied, and turns left or right when the steering wheel moves. Based on these attributes and behaviors, we can carry out a classification of this object – it belongs to a class called Car. In programming, the technique to design and build an application by focusing on objects that interact with each other is known as object-oriented programming. In the object-oriented paradigm, class and object are two terms that are used quite often and it is very important for programmers to understand the difference between them.