Migrating a Vaadin application to GAE


I’m trying to migrate my existing application to GAE using this

When trying to set the application ID, I get following error message:

Cannot set application ID (appengine-web.xml is missing)

I suppose that the reason for this is that I have to set the deployment mode of the Vaadin app to “GAE”.

But how can I do this for an EXISTING (not new) project?

Thanks in advance


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