When the kie-server connects to the controller / workbench via web-sockets and this connection fails (e.g., due to network problems), the kie-server will try to reconnect.
Reconnect thread started in WebSocketClientImpl (kie-server-controller-websocket-common), fails with NPE with log message: WebSocketClientImpl: Unable to reconnect to the controller through the Null socket because of null

NPE is thrown because session.getRequestURI returns NULL value
at this.session = container.connectToServer(this, this.config, session.getRequestURI());

In my case kie-server (WebSocketContainer) running on tomcat 8.5