So our app is in Vaadin 7. Looking at moving it to Vaadin 8, I see there are no more …
Connection Pools?
Containers?
Items?
Properties?
Some methods in my Model return Containers, some return an Item. So I guess I rewrite these to return lists or single objects?
Looks like some of the UI components no longer take lists?
I see there are no more …Connection Pools?Containers?Items?Properties?
Yes, they are no more in Vaadin 8 core. Instead there are DataProviders, which replaces Containers, and components using Containers like Grid, ComboBox, etc. have been modified to use DataProviders instead. Also FieldGroup is no more, instead there is new Binder concept. Fields have been simplified a little.
However, for gradual migration, there is optional compatibility library package for Vaadin 8, which contains Vaadin 7 legacy classes. This makes possible to create hybrid application as quick migration. You get functional app, which does not yet exploit Vaadin 8 goodies, but you can migrate view by view.
Some methods in my Model return Containers, some return an Item. So I guess I rewrite these to return lists or single objects? Looks like some of the UI components no longer take lists?
Yes, when migrating to Vaadin 8, you need to rework those. Vaadin 8 DataProvider model is luckily step towards simpler way of doing things as you have noted, Collections and Beans as it should be in Java. As a bonus you get better typesafety.