You should maybe go back and read
this chapter of the Book of Vaadin
. If you know how to get your Vaadin app running through an IDE and don’t know anything else (e.g., that Java web apps are packaged as .war files), then it’s great at first, but you’re asking for trouble later.
I’d recommend taking one day and learning a little about Java web applications. Learn to build a simple “Hello world” style servlet app (just one class and optional web.xml). Then shut off your IDE and learn how to deploy, undeploy, and access the app using tomcat or glassfish and a browser. Tomcat is the reference implementation for Java EE web apps and GlassFish is the impl for Java EE (meaning web plus EJB plus others) apps. Either one would do fine.
Things will make a lot more sense to you later if you know just a little bit about servlets, the servlet container, and http sessions. Then have fun with Vaadin and learn about more advanced things later. If you’re using an IDE, then I’m sure it already has tutorials you can take about Java web apps. If not, Google around for “Java web app tutorial” and you’ll find plenty.
Cheers,
Bobby