code: @Override
      public boolean userPropertyExists(String name) {
          if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled())
              SibTr.entry(this, tc, "userPropertyExists", name);
  
          boolean result = false;
  
          /* If the name is null there is nothing to do. so only proceed if it is */
          /* supplied. */
          if (name != null) {
  
              /* Got to check Maelstrom's transportVersion first as performance for it */
              /* is critical. */
              if (name.equals(MfpConstants.PRP_TRANSVER) && isTransportVersionSet()) {
                  result = true;
              }
              /* otherwise, first try the JMS user property map as the most likely */
              else if ((mayHaveJmsUserProperties()) && (getJmsUserPropertyMap().containsKey(name))) {
                  result = true;
              }
              /* then try the non-JMS user property map */
              else if ((mayHaveOtherUserProperties()) && (getOtherUserPropertyMap().containsKey(name))) {
                  result = true;
              }
          }
  
          if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled())
              SibTr.exit(this, tc, "userPropertyExists", result);
          return result;
      }
docs: /*
  Return a boolean indicating whether a User Property with the given name
  exists in the message.
  
  Javadoc description supplied by JsApiMessage interface.