code: public static void writeFlowId(Message message, String flowId) {
          if (!(message instanceof SoapMessage)) {
              return;
          }
          SoapMessage soapMessage = (SoapMessage)message;
          Header hdFlowId = soapMessage.getHeader(FLOW_ID_QNAME);
          if (hdFlowId != null) {
              LOG.warning("FlowId already existing in soap header, need not to write FlowId header.");
              return;
          }
  
          try {
              soapMessage.getHeaders().add(
                      new Header(FLOW_ID_QNAME, flowId, new JAXBDataBinding(String.class)));
              if (LOG.isLoggable(Level.FINE)) {
                  LOG.fine("Stored flowId '" + flowId + "' in soap header: " + FLOW_ID_QNAME);
              }
          } catch (JAXBException e) {
              LOG.log(Level.SEVERE, "Couldn't create flowId header.", e);
          }
  
      }
docs: Write flow id to message.
  
  @param message the message
  @param flowId the flow id