Order Calculator Graphical User Interface (GUI) is a Java program file that provides a graphical interface for calculating orders. This file can be used to develop applications that require order calculation functionalities. The GUI allows users to input order details, such as item quantities and prices, and performs the necessary calculations to determine the total order amount. It also includes features like error handling and validation to ensure accurate calculations. With Order Calculator GUI, developers can easily create user-friendly order calculation systems for their applications.