Tasks Task 1: (2 mark) Complete/update the program design based on the given UML class diagram. You CANNOT modify or delete any existing class, interface, attributes, and methods. You can add new classes, associations, and methods. Complete the UML activity diagram. Task 2 (6 marks): Implement the system according to the UML class diagrams. The program shall assume the customer's inputs are always correct and valid. be consistent with the UML class diagrams. follow the conventions for naming all classes, variables, and methods. provide sufficient comments. use proper blank spaces, indentation, and braces to make your code easy to read and understand. . follow the specified steps. be able to repeat the main menu until the customer exists the system. . be implemented by using the advanced OOP features such as inheritance, polymorphism, abstraction, interface, and instanceof class. Task 3 (2 marks): Compilation and test. Please carefully compile your program and make sure your program can pass the compilation by using "javac" command. Test your program to all the items in the main menu. Please do not define the package in your program (a special alert for students who use IDE to complete the assignment)