code: void setMessage(MessageImpl msg) {
      if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled()) SibTr.entry(this, tc, "setMessage", msg);
      theMessage = msg;
      if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled()) SibTr.exit(this, tc, "setMessage");
    }
docs: Set the back-pointer to the MFP message that contains this JMO instance.
  
  @param msg The MessageImpl of this JMO's container