Singleton for each vaadin session?

Is it possible to have a singleton pattern in a vaadin application, which is unique for each user (browser) session?

That is exactly what the Application class is. There is one Vaadin application class per HTTP session.

Yes it is, you’ll need to use the ThreadLocal pattern to implement it. See
this blog post
for details and an example.

Thank you for the quick answers… the ThreadLocal pattern is exactly what I was looking for!