code: @Override
      public void doUpgrade(HttpServletRequest request, HttpServletResponse response, ServerEndpointConfig endpointConfig, Map<String, String> pathParams) throws ServletException, IOException {
  
          wsocUpgradeHandler.handleRequest(request, response, endpointConfig, pathParams, true);
          if (!response.isCommitted()) {
              response.getOutputStream().close();
          }
  
      }
docs: /*
  (non-Javadoc)
  
  @see com.ibm.websphere.wsoc.WsWsocServerContainer#upgrade(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse, javax.websocket.EndpointConfig,
  java.lang.String)