Answer Happy

create a simple billing system java
(5 pts) Main/Start Java (.java) file (10) File Input & output(Reading data from a file Writing data to a file (10 pts) Use of 2 cases of abstraction (10 pts) Use of 2 cases of encapsulation (5 pts) Use of 1 case of inheritance (5 pts) Use of 1 case of Polymorphism (10 pts) Use of 2 abstract classes (10 pts) Use of 2 Interfaces (20 pts) GUI (5 different widgets/graphical elements such a label, menu, frame, button, dialog, etc.) (10 pts) Event-driven- programming • 1 case of keyboard input handling • 1 case of mouse (move or button click) handling (10 pts) Handling bad data • One example of testing for bad data entry • One example of using try-except-finally • One example of handling bad data file handling