(Modified GradeBook Class) Modify class GradeBook (Fig.) as follows:a) Include a String in...

(Modified GradeBook Class) Modify class GradeBook (Fig.) as follows:

a) Include a String instance variable that represents the name of the course’s instructor.

b) Provide a set method to change the instructor’s name and a get method to retrieve it.

c) Modify the constructor to specify two parameters—one for the course name and one for the instructor’s name.

d) Modify method displayMessage to output the welcome message and course name, followed by "This course is presented by: " and the instructor’s name.

Use your modified class in a test application that demonstrates the class’s new capabilities.

Fig. | GradeBook class with a constructor to initialize the course name.