java82.java

public static Map<Character, Integer> signature(String s) {
    Map<Character, Integer> result = new HashMap<Character, Integer>();

    s.chars().forEach((int i) -> {
        char c = Character.toChars(i)[0];
        Integer count = result.get(c); 
        if ( count == null) {
            result.put(c, 1);
        } else {
            result.put(c, count+1);
        }
    });

    return result;
  
}