477c071af9
https://build.spring.io/browse/INTSAMPLES-NIGHTLY-2413 When we fail with the `java.net.BindException: Address already in use (Bind failed)` in the `TcpNetServerConnectionFactory.run()`, the `serverSocket` property remains `null` and we get `NPE` in the `catch` block trying to `close()` the socket. * Call `stop()` instead which has all the required protections. **Cherry-pick to 5.0.x and 4.3.x**