In this exercise, you’ll use netbeans to develop a gui version of the

In this exercise, you’ll use NetBeans to develop a GUI version of the Invoice application you saw earlier in this book. When you’re done, the user interface for this application should look something like this: Open the project named ch 15_ex2_Invoice in the ex_starts directory, and review the code for this project. Add a form named InvoiceForm to the murach.forms package. Then, use Design view to add, size, and align the required controls, and set the control and form properties so they look as shown above. Set the variable names for the controls that you’ll need to access from the Java code. Then, display the form to make sure it looks the way it should. Add import statements for the Calculations and java.text.NumberFormat classes. Add an event handler for the actionPerformed event of the Calculate button. Add code to this event handler that gets the customer type and subtotal from the form, uses the calculate DiscountPct method in the invoice Calculations class to calculate the discount percent based on those values, calculates the discount amount and total, and formats and displays the values on the form. Add an event handler for the action Performed event of the Exit button that exits the application. Then, run the form and test it to be sure it works with valid data. Add code that uses the methods of the SwingValidator class to check that the user enters values in the Customer Type and Subtotal text fields and that the Subtotal text field is a double value. Add code to the main method that centers the form when it’s displayed. Then, run the form again to be sure it works properly.