Java tutorial
import java.util.HashMap; public class Main { public static void main(String[] args) { HashMap<Character, Integer> map = new HashMap<Character, Integer>(); String test = "BUNANA"; char[] chars = test.toCharArray(); for (int i = 0; i < chars.length; i++) { if (!map.containsKey(chars[i])) { map.put(chars[i], 1); } map.put(chars[i], map.get(chars[i]) + 1); } System.out.println(map.toString()); } }