Designing for object-oriented programming

- As you know, Java is considered an Object-Oriented programming language, but what does that really mean? Classes and Objects are the main focus of this section. A Class is a blueprint for an object. Classes are used to represent the State and Behavior of that object. For example, if we have a Person Class, the person would have a State, which might be their Name or their Age or both, and they'll have a Behavior, such as maybe we need to change the name.

They got married or it was spelled incorrectly when the person was first added, or maybe we need to update their age. So a person has some state values, some attributes, Name, Age, and Behaviors, that we will use to update the data for this person. Change their name or update their age. We use Classes to model Real-world objects, such as Bank accounts, Vehicles, Animals, Inventory, and Movies, just to name a few.

Each class contains Instance data, Constructors, which are special methods used to build an instance of our class, and Methods, the blocks of code common to all objects of this class that represent the object's behavior.