初学Java 数组统计字母

 public class CountLetterInArray {
   public static void main(String[] args) {
       char[] chars = createArray();

       System.out.println("The lowercase letters are: ");
       displayArray(chars);

       int[] counts = countLetters(chars);

       System.out.println(" ");
       System.out.println("The occurrences of each letter are: ");
       displayCounts(counts);
   }

   public static char[] createArray() {
       char[] chars = new char[];
       for(int i=; i<chars.length; i++) {
           chars[i] = RandomCharacter.getRandomLowerCaseLetter();
       }
       return chars;  

   }
   public static void displayArray(char[] chars) {
       for(int i=; i<chars.length; i++) {
           if((i+)%==)
             System.out.println(chars[i]);
           else
               System.out.print(chars[i]+" ");
       }
   }
   public static int[] countLetters(char[] chars) {
      int[] counts = new int[];

      for(int i=; i<chars.length; i++) {
          counts[chars[i]-'a']++;
      }
      return counts;
   }
   public static void displayCounts(int[] counts) {
       for(int i=; i<counts.length; i++) {
           if((i+)%==)
               System.out.println(counts[i]+" "+(char)(i+'a'));
           else
               System.out.print(counts[i]+" "+(char)(i+'a')+" ");
       }
   }
 }