docs: public final String getJmsType() {
          if (getHdr2().getChoiceField(JsHdr2Access.JMSTYPE) == JsHdr2Access.IS_JMSTYPE_EMPTY) {
              return getDerivedJmsType();
          }
          else {
              return (String) getHdr2().getField(JsHdr2Access.JMSTYPE_DATA);
          }
      }