The "Calculator.java" file contains the code for a Java WindowBuilder application code which performs the basic functions of a calculator(Addition, Subtraction, Multiplication and Division).
The WindowBuilder is used in creating desktop applications providing a window for application with various features like buttons, text areas, tables etc.
The basic structure of this project is - a desktop window that contains a Jframe which holds all the buttons of a standard calculcator. There are two text areas, one to display the ongoing calculation and the other one is to receive input and to display end results of the calculation.