achot-string-count.java

package com.company;

import java.io.PrintStream;
import java.util.HashMap;
import java.util.Map;

public class Main {

    static void hist(String codes, PrintStream out) {
        Map<Character, Integer> map = new HashMap<>();

        String letters = "uwxz";
        for (int i = 0; i < letters.length(); i++)
            map.put(letters.charAt(i), 0);

        for (int i = 0; i < codes.length(); i++) {
            map.computeIfPresent(codes.charAt(i), (ch, count) -> count + 1);
        }

        for (Map.Entry<Character, Integer> me : map.entrySet()) {
            Integer n = me.getValue();
            if (n > 0) {
                out.format("%c  %-5d%s%n", me.getKey(), n, iter(n));
            }
        }
    }

    public static String iter(int n) {
        StringBuilder billder = new StringBuilder();
        String a = "*";
        for (int i = 0; i < n; i++) {
            billder.append(a);
        }
        return billder.toString();
    }

    public static void main(String[] args) {
        hist("axuwxzzzzzzzzzzz", System.out);
    }
}