The third programming project involves writing a program that produces a road trip cost estimator with a GUI interface. The required GUI is shown below:$$The text fields above the Calculate button are the input fields and the one below is the output field. The output field should not be editable. Three of the input fields have combo boxes to their right, which allow the data to be input as described below:$$ The distance can be entered in either miles or kilometers$$ The gasoline cost can be input in either dollars per gallon or dollars per liter$$ The gas mileage can be input as either miles per gallon or kilometers per liter$$The necessary calculations are as follows;$$gasoline cost $=$ gasoline cost$$total trip cost $=$ gasoline cost $+($hotel cost $+$ food cost$)$ number of days $+$ attractions$$Your program should consist of two classes. The first class Project$3$ should define the GUI illustrated above. The second class TripCost should be an immutable class that has at a minimum a constructor that creates a trip cost object and a method that computes and returns the total trip cost.$$You are to submit two files.$1.$ The first is a $.$zip file that contains all the source code for the project. The $.$zip file should contain only source code and nothing else, which means only the $.$java files. If you elect to use a package the $.$java files should be in a folder whose name is the package name. Every outer class should be in a separate $.$java file with the same name as the class name. Each file should include a comment block at the top containing your name, the project name, the date, and a short description of the class contained in that file.$2.$ The second is a Word document $($PDF or RTF is also acceptable$)$ that contains the documentation for the project, which should include the following:$$a$.$ A UML class diagram that includes all classes you wrote. Do not include predefined classes$$b$.$ A test plan that includes test cases that you have created indicating what aspects of the program each one is testing$$c$.$ A short paragraph on lessons learned from the project