code: private String getReadonlyDisplayValue(final Object value, final HtmlCheckBox checkBox) {
          final StringBuilder sb = new StringBuilder();
          if (StringUtils.isNotEmpty(checkBox.getDescription())) {
              sb.append(checkBox.getDescription()).append(": ");
          }
          sb.append((Boolean) value ? "ja" : "nein");
          return sb.toString();
      }
docs: Should return value string for the readonly view mode. Can be overridden
  for custom components.