Scanner issue and how do I use variable "userName" in print statements?

Question

This is my first time posting. I'm taking my first programming class and am having an issue. My IDE doesn't show any bugs but when I run this code, it's not running past the user input for name. I get this error...

Exception in thread "main" java.util.NoSuchElementException: No line found
        at java.base/java.util.Scanner.nextLine(Scanner.java:1651)
        at LAB.getString(LAB.java:38)
        at LAB.getInteger(LAB.java:46)
        at LAB.main(LAB.java:13)"

It's after the user is asked to input their name, it will re-ask the question and give me the above error message. I'm still very new to this and don't understand. Here's the code. Also, That whole piece of code is supposed to set the input to the variable "userName" but it won't let me use "userName" anywhere, why? Any help is very much appreciated.

import java.util.Random;
import java.util.Scanner;
    
    public class LAB {
        public static void main(String[] args) {
            // Declare Variables
            int number = 0;
            int answer = 0;
            int difference = answer - number;
          
          // Call Modules
          welcomeMessage();
          getString();
          getInteger();
    
          // If number is less than 0, return error and exit program
          if (number < 0) {
              System.out.println("Error");
              System.exit(0);
          }
          
          // Call Modules
          randomNumber();
          displayResult(answer, number, difference);
          goodbyeMessage();
     
        }
        
        // Welcome Message Module
        public static void welcomeMessage() {
            System.out.println("*** WECOME TO THE TOY STORY ALIEN GUESSER GAME ***");
            System.out.println("You must guess the number of Toy Aliens in the Gumball...);
        }
    
        // Get Username Module
        public static String getString() {
            Scanner keyboard = new Scanner(System.in);
            System.out.println("Contestant Name?: ");
            String userName = keyboard.nextLine();
            keyboard.close();
            return userName;
        }
    
        // Get User Guess Module
        public static int getInteger() {
            Scanner keyboard = new Scanner(System.in);
            System.out.println("Ok " + getString() + ", How many Aliens do you think are...); 
            int number = keyboard.nextInt();
            keyboard.close();
            return number;
        }
    
        // Generate Random Number Module
        public static int randomNumber() {
            Random rand = new Random();
            final int MAX = 1000;
            int answer = rand.nextInt(MAX) + 1;
            return answer;
        }
    
        // Display the Result
        public static void displayResult(int answer, int number, int difference) {
            if (answer == number) {
                System.out.print("Great Guess! Are you a Psychic? That is the exact number of"); 
                System.out.print("Aliens...YOU WIN");
            }
    
            else {
                System.out.print("Good Try " + getString() + ", But there are actually  "); 
                System.out.print("+ answer + " Aliens in the Gumball Machine. You were off"); 
                System.out.print("by " + difference + ".");
            }
        }
        // Goodbye Message
        public static void goodbyeMessage() {
            System.out.println("Thank you for playing.");
        }
    
    }