docs: public static String getRequiredCheck(int order, Field field) {
          String fieldName = getFieldName(order);
          String code = "if (" + fieldName + "== null) {\n";
          code += "throw new UninitializedMessageException(CodedConstant.asList(\"" + field.getName() + "\"))"
                  + ClassCode.JAVA_LINE_BREAK;
          code += "}\n";
  
          return code;
      }