I want to create a GUI for a checkout system and refactor the code that it reads in all known articles from externally sources. The external information for categories and articles can be either in text files or in a SQLite database The application should at least allow to edit the prices of known articles $($make those changes persistent!$)$ You have to provide manners of selecting articles and add those a user$-$specified number of times to the current receipt. The application should visually represent the current receipt. Extend the application by one middle$-$complexity, sense$-$makingfeature$($e$.$g$.$ customer database and you record all sales for each customer, or the GUI $($product button grid$)$ is creating itself based on the know items$).$ How can I implement this is Java$/$Processing Language