Serialization Issues when running spring starter

[manolo]

• Checkout the skeleton-starter-flow-spring
• run mvn spring-boot:run
• load the application in browser
• Change the button label in MainView.java in your IDE
• wait for spring devtools to restart the servlet container
• Each time the server reloads, there is an error in console

2019-06-26 19:09:32.459  WARN 8560 --- [  restartedMain] o.a.c.c.C.[Tomcat].[localhost].[/]       :
 Cannot deserialize session attribute [com.vaadin.flow.server.VaadinSession.springServlet]
 for session [319A4C794323F4228EBFCE5DD22E6FCC]

[denis-anisimov]

This is not a Flow issue.
This is a starter issue : the click listener in the button is not serializable because MessageBean is not serializable. If one changes the listener so that it doesn't use not serializable class then everything is OK.