Defining classes
In the Smalltalk development environment, you generally define a class (or create a defined class) by subclassing from an existing class. 
Defining a class consists of the following activities: 
•You must specify a containing application for the class. 
•You must be a group member of this application. 
•You must give the class a unique name. No two classes in your image can have the same name. 
When you create a class, you become its owner. 
Last modified date: 01/29/2015