code: public static String displayParts(Object... parts) {
          StringBuilder builder = new StringBuilder("[");
          boolean first = true;
          for (Object part : parts) {
              if (first) {
                  first = false;
              } else {
                  builder.append('|');
              }
              if (part == null) {
                  builder.append('?');
              } else {
                  builder.append(display(part));
              }
          }
          builder.append(']');
          return builder.toString();
      }
docs: Displays the given parts with a bit of syntactic sugar.
  @param parts The parts to display
  @return The string that displays the given parts