I recently encountered this problem in one of our project where vaadin is used for UI(forced by my leads to use it). Issue is vaadin 7 is very slow. rendering takes 5 to 6 seconds for normal screen… With many components, it take more time… Do u have any solution? https://showbox.tools/
https://trackeasy.fun/usps/
Other than reducing the number of components per page, one way to alleviate slow loading time is to use Server Push: https://vaadin.com/docs/v7/framework/advanced/advanced-push.html
The idea then would be to break down the UI into smaller chunks. First, load the page with the first few components that the user is likely to interact with, then update the UI with the rest of the components (over one or several calls).