Create an exception for illegal Roman numerals Create a class called Illegal Roman Numeral Exception that extends Illegal Argument Exception as shown in lecture.
Use a GUI to open the file for displaying the Roman numerals Modify your Roman Numeral GUI so that it will be a complete J Frame with a menu bar and menus. There should be two menus: one called File and another called Convert. The File menu should have the menu items Open and Quit. […]