The first few lines of a class Factorial, which has a text field and a label, are shown below. public class Factorial extends JFrame implements ActionListener \{ private JTextField text = new JTextField(2); private JLabel label = new JLabel ("I=e); The expected appearance of the frame, after a number 5 is input and Enter is pressed, is: 51=120 (a) Write a program segment (in a method of Factorial) to display the text field and the label in a frame and add Factorial as the action listener of the text field. (b) Write a program segment of the action listener to display the correct result of n! as shown above, where n is the number input in the text field (assume it is a positive integer). The class FactorialCalculator and its method factorial(int n ) can be used directly