The development environment allows you to categorize methods. You can use method categories to organize the list of methods defined by a class. For example, VisualAge uses category names that identify which application the method comes from. Also, category names in VisualAge end with either API or Internal. You are free to use and package any methods categorized as API. Methods categorized as Internal, however, are not part of the official Application Programming Interface for that object.
You or your team might want to develop a strategy for categorization. For example, a categorization scheme might include categories such as Accessing, Printing, Testing, and User Interface. It is also possible not to use categories at all.
Let's categorize the method you just added to the class String:
When you categorize methods, it is possible to select more than one category for a given method.
Categorize the methods in STCalculator as follows: