Ans. I think object oriented Methodology suits
Ans the Following are the design principle
6. Always keep your target users in mind as the product is designed.
8. Provide the ability to undo and redo actions.
The transactions between users and the bank for buying of product must be secure
The web pages must be platform independent JSP provides platform independence.
Follow Coding principles Such as comment indentations etc. that the people who are going to update or maintain the code must be able to so there work without trouble.
Provide Simple user interface so that even a layman can do the transactions.