code: protected void doResponse(SipServletResponse response)
        throws ServletException, IOException {
  
      logger.info("SimpleProxyServlet: Got response:\n" + response);
      if(SipServletResponse.SC_OK == response.getStatus() && "BYE".equalsIgnoreCase(response.getMethod())) {
        SipSession sipSession = response.getSession(false);
        if(sipSession != null) {
          SipApplicationSession sipApplicationSession = sipSession.getApplicationSession();
          sipSession.invalidate();
          sipApplicationSession.invalidate();
        }     
      }
      else if ( response.getStatus() >= 400) {
        doErrorResponse(response);
      }
    }
docs: {@inheritDoc}