Generating Lowercase Letters Randomly and Couting the Occurence of Each in Java

Problem:

Write a program that generates one hundred lowercase letters randomly and

counts the occurrences of each letter:

Output:

The lowercase letters are:
q u q i s a y n o j f o x i a o x m x n
x e n y l i b f h h r p j y c m q d b q
o i a z j a a w a b z e w s d g v u v b
y n a q s p f k d i f d d c z l z l j a
q w j v j m w f t e g z z x z l v f o i

The occurrences of each letter are:
8 a 4 b 2 c 5 d 3 e 6 f 2 g 2 h 6 i 6 j
1 k 4 l 3 m 4 n 5 o 2 p 6 q 1 r 3 s 1 t
2 u 4 v 4 w 5 x 4 y 7 z

Solution:

import java.util.Random;

 public class Count {
   /** Main method */
   public static void main(String args[]) {
     // Declare and create an array
      char[] chars = createArray();

     // Display the array
     System.out.println("The lowercase letters are:");
      displayArray(chars);
     // Count the occurrences of each letter
     int[] counts = countLetters(chars);
     
     // Display counts
     System.out.println();
     System.out.println("The occurrences of each letter are:");
      displayCounts(counts);
   }

   /** Create an array of characters */
   public static char[] createArray() {
     // Declare an array of characters and create it
     char[] chars = new char[100];
     Random generator = new Random();
     // Create lowercase letters randomly and assign
     // them to the array
     String S ="abcdefghijklmnopqrstuvwxyz";
     for (int i = 0; i < chars.length; i++) 
       chars[i] = (char) S.charAt(generator.nextInt(26));
     // Return the array
    return chars;
   } 
  
   /** Display the array of characters */
   
 public static void displayArray(char[] chars) {
     // Display the characters in the array 20 on each line
     for (int i = 0; i < chars.length; i++) {
       if ((i + 1) % 20 == 0)
         System.out.println(chars[i] + " ");
       else
        System.out.print(chars[i] + " ");
            }
          }
       
          /** Count the occurrences of each letter */
          public static int[] countLetters(char[] chars) {
            // Declare and create an array of 26 int
            int[] counts = new int[26];
       
            // For each lowercase letter in the array, count it
            for (int i = 0; i < chars.length; i++) 
              counts[chars[i] - 'a']++;
       
            return counts;
          }
       
          /** Display counts */
          public static void displayCounts(int[] counts) {
            for (int i = 0; i < counts.length; i++) {
              if ((i + 1) % 10 == 0)
                System.out.println(counts[i] + " " + (char)(i + 'a'));
              else
                System.out.print(counts[i] + " " + (char)(i + 'a') + " ");
            }
          }
       }