code: private static final StringBuilder convertToAbbr(StringBuilder sb, String name) {
          sb.append(Character.toUpperCase(name.charAt(0)));
          sb.append(name.charAt(1)).append(name.charAt(2));
          return sb;
      }
docs: Converts the given name to its 3-letter abbreviation (e.g.,
  "monday" -> "Mon") and stored the abbreviation in the given
  <code>StringBuilder</code>.