code: private QName getDefaultQName(String localPart) {
          if (StringUtils.hasText(defaultNamespaceUri)) {
              return new QName(defaultNamespaceUri, localPart, defaultPrefix);
          } else {
              throw new SoapHeaderException("Failed to add SOAP header '" + localPart + "', " +
              		"because neither valid QName nor default namespace-uri is set!");
          }
      }
docs: Get the default QName from local part.
  @param localPart
  @return