code: public static void join(StringBuilder sb, Object[] array, String delimiter) {
          if (empty(array)) { return; }
          sb.append(array[0]);
          for (int i = 1; i < array.length; i++) {
              sb.append(delimiter);
              sb.append(array[i]);
          }
      }
docs: Joins the items in array with a delimiter, and appends the result to StringBuilder.
  
  @param sb StringBuilder to append result to
  @param array array of items to join.
  @param delimiter delimiter to insert between elements of array.