public static String deleteAny(String inString, String charsToDelete) {
        if (!hasLength(inString) || !hasLength(charsToDelete)) {
            return inString;
        }
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < inString.length(); i++) {
            char c = inString.charAt(i);
            if (charsToDelete.indexOf(c) == -1) {
                sb.append(c);
            }
        }
        return sb.toString();
    }
Delete any character in a given String.

@param inString      the original String
@param charsToDelete a set of characters to delete.
                     E.g. "az\n" will delete 'a's, 'z's and new lines.
@return the resulting String
src/main/java/spark/utils/StringUtils.java