PROGRAMMING LANGUAGE: Java

A retail store has a preferred customer plan where customers can earn discounts on all their purchases. The amount of discount depends on customer's cumulative purchases in the store and the business rules for discounts is as follows:

• When a preferred customer spends $500, he or she gets a 5 % discount on all future purchases.
• When a preferred customer spends $1000, he or she gets a 6 % discount on all future purchases.
• When a preferred customer spends $1500, he or she gets a 7 % discount on all future purchases.
• When a preferred customer spends $2000, he or she gets a 10 % discount on all future purchases.

Design a class called PreferredCustomer, which is derived from the Customer class you created in No 3. The PreferredCustomer class should have properties for the amount of the customer's purchases and the customer's discount level. Demonstrate the class in a simple GUI application.

• Write the code include appropriate input validation, error and exception handling code.
• Test Plans