code: public static String stringifier(Object bean) {
          StringBuilder sb = new StringBuilder();
          List<Field> fields = getAllFields(new LinkedList<Field>(),
                  bean.getClass());
          sb.append(bean.getClass().getName() + "[");
          for (Field field : fields) {
              field.setAccessible(true);
              String name = field.getName();
              Object value = null;
              try {
                  value = field.get(bean);
              } catch (IllegalArgumentException e) {
                  log.warn("IllegalArgumentException", e);
              } catch (IllegalAccessException e) {
                  log.warn("IllegalAccessException", e);
              }
              if ("otherAttributes".equals(name)
                      && ((HashMap<?, ?>) value).isEmpty()) {
                  value = null;
              }
              if (value != null) {
                  sb.append(name);
                  sb.append("=");
                  sb.append(value);
                  sb.append(" ");
              }
          }
          sb.append("]");
          sb.append(System.getProperty("line.separator"));
          return sb.toString();
      }
docs: <p>
  FOR DEBUG. This method does not include the field of a null object in the
  returned string.
  see {@link org.mixer2.xhtml.AbstractJaxb#toString()}
  </p>
  <p>
  デバッグ用です。このメソッドは文字列表現に null オブジェクトを持つフィールドを加えません。
  </p>
  
  @param bean org.mixer2.jaxb.xhml.* class instance.
  @return