Design a stock control system using BLUEJ for a retail organisation that sells goods to the public.

Organisation sells two categories of product. Ultimately the program will maintain at list of these two categories of phones in an array and will provide a menu driven system to allow customers browse the goods on offer and buy them if they wish and also to allow the organisation update stock levels if they wish. This solution will involve inheritance with a super (general) class and two subclasses (specialized classes).