code: @Override
      public Object getJMSXGroupSeq() {
          if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled())
              SibTr.entry(this, tc, "getJMSXGroupSeq");
          Object result = null;
  
          if (mayHaveMappedJmsSystemProperties()) {
              result = getObjectProperty(SIProperties.JMSXGroupSeq);
          }
  
          if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled())
              SibTr.exit(this, tc, "getJMSXGroupSeq", result);
          return result;
      }
docs: getJMSXGroupSeq
  Return the value of the JMSXGroupSeq property if it exists.
  We can return it as object, as that is all JMS API wants. Actually it only
  really cares whether it exists, but we'll return Object rather than
  changing the callng code unnecessarily.
  
  Javadoc description supplied by JsJmsMessage interface.