title: Collections.reverse method not reversing entry
body: <p>My code below is supposed to accept an integer from the user, and then print whatever integer they enter in reverse order. I am getting no errors, but when I run this program the integer is not being printed in reverse. Can someone please help me figure out why?</p>
  
  <pre><code>import java.util.*;
  
  public class ReverseDigits {
  
      public static void main(String[] args) {
          Scanner sc = new Scanner(System.in);
          String response;
  
          System.out.println("Please enter a whole number.");
          response = sc.next();
  
          reverseDigit(response);
      }
  
      public static void reverseDigit(String digit) {
          ArrayList al = new ArrayList();
          al.add(digit);
          Collections.reverse(al);
          System.out.println("Your number in reverse order is: " + al);
      }
  
  }
  </code></pre>