code: public String format() {
      if (SipSession.isInternal(returnCode) == true) {
        return SipSession.statusCodeDescription.get(new Integer(returnCode))
            + (errorMessage.length() > 0 ? (": " + errorMessage) : "");
      } else {
        return "Status code received from network = " + returnCode + ", "
            + SipResponse.statusCodeDescription.get(new Integer(returnCode))
            + (errorMessage.length() > 0 ? (": " + errorMessage) : "");
      }
    }
docs: /*
  @see org.cafesip.sipunit.SipActionObject#format()