Feature

Illustrates concept

Bob is a man (an object).

Objects

Bob's date of birth is June 1, 1980, gender - male, and hair - black.

Properties

Bob can eat, sleep, drink, dream, talk, and calculate his own age.

Methods

Bob is an instance of the Programmer class.

Class (in classical OOP)

Bob is based on another object called Programmer.

Prototype

(in prototypal OOP)

Bob holds data, such as birth_date, and methods that work with the data, such as calculateAge().

Encapsulation

You don't need to know how the calculation method works internally. The object might have some private data, such as the number of days in February in a leap year. You don't know, nor do you want to know.

Information hiding

Bob is part of a WebDevTeam object together with Jill, a Designer object, and Jack, a ProjectManager object.

Aggregation and composition

Designer, ProjectManager, and Programmer are all based on and extend a Person object.

Inheritance

You can call the methods Bob.talk(), Jill.talk(), and Jack.talk(), and they'll all work fine, albeit producing different results. Bob will probably talk more about performance, Jill about beauty, and Jack about deadlines. Each object inherited the method talk from Person and customized it.

Polymorphism and method overriding