Class Vs Object

Class
A class is a family of objects. If several objects have similar structure, behavior, and meaning, then you can group the objects into a class—in effect, a template (or even a factory) you can use to create uniform individual objects. When you develop an object-oriented system, the system is described as being made up of classes—and that’s even true of a real-life enterprise system. Some examples of classes might be the Crash Dummy class, Lease class, Client class, or Owner class. Each class provides a generic scheme for one or more objects, and a class can be a template for many objects or only one.

Object
Object is an instance of the class.
An object can be any useful item that has identity, structure, and behavior. When an object-oriented software system is running, the items in the system are interacting software objects. When a real-life physical enterprise is in operation, the individual interacting entities in the enterprise system are the business objects.

UML Diagram List

UML Introduction

The Unified Modeling Language (UML) is a graphical language used to visualize the software engineering process. UML was invented in 1994 and it has been build up to version 2.0 and still researching by the Object Management Group.

I've been started learning UML since 2004 when I was studying Software Engineering for my Master Degree. Start from 2005, I've been using it practically for software development and I found out that it's very useful for me to explain the software design in UML instead of explain in textual language.

When i join the UML Modeling Tool development company in year 2007, I get to know more about UML and its rules. Even thought UML have over dozen of diagrams, not many people are using all of them. Mostly we use Use-Case Diagram, Activity Diagram and Class Diagram. State-Machine Diagram, Package Diagram, Sequence Diagram and Deployment Diagram are also useful for the developers to show the application process and flows.

There are a lot of resources for UML modeling language out there and the purpose of this blog is to explain the detail rules for each diagram and the usage of all the symbols.

The example and tutorial in this blog are based on my own experiences and my practical usage. The explanation of the diagram and symbols are reference from the UML Reference Books.