In this section, we have learned that classes act as blueprints for objects. When we define a class, we decide what attributes and behaviors (methods) should be associated with the objects. Then when instances of the class are created they have those state and behavioral properties.

We worked through a few tasks such as:

• Creating a domain model with different types of object associations

• Writing instance methods that manipulate nested data structures

• Building a fully functional object-oriented program

We also introduced code design principles that object-oriented programmers commonly use. With this knowledge, we are able to use the domain model to write maintainable code in larger scale applications.