Vaadin 10 for new project

While Vaadin 10 Bakery App Starter does a good job demonstrating the new features of the framework, it is heavily based on PolymerTemplate and maybe it's not the best example if you are looking for some code more similar to Vaadin 8.

Actually, writing a Java-only UI is still as simple as it was in the previous versions. For instance, the MainView class described in the Vaadin Flow Tutorial (excerpt below) contains a Grid and doesn't require writing HTML or JS.

If you go with this approach, you may base your application in the Skeleton Starter App, and replace the ExampleTemplate (polymer) with your own layouts defined in Java code.

@HtmlImport("styles/shared-styles.html")
@Route("")
@Theme(Lumo.class)
@BodySize(height = "100vh", width = "100vw")
public class MainView extends VerticalLayout {
    private CustomerService service = CustomerService.getInstance();
    private Grid<Customer> grid = new Grid<>();

    public MainView() {
       grid.setSizeFull();

       grid.addColumn(Customer::getFirstName).setHeader("First name");
       grid.addColumn(Customer::getLastName).setHeader("Last name");
       grid.addColumn(Customer::getStatus).setHeader("Status");

       add(grid);

       updateList();
   }

   //etc...
}

Give the 10 a try!

Yes, it's true. We do not provide starters with Java-only UI, yet. But this does not mean that it is not possible with Vaadin 10. Javier gave a good example already. And we are working on new starters all the time and will allow 3rd party starters in the future, too.

For the migration, please have a look at https://vaadin.com/docs/v10/flow/migration/1-migrating-v8-v10.html. It should give you a good overview.

Besides that, Vaadin 10 reached beta status and we plan a final release this year.

If you never worked with Vaadin at all I would suggest to use Vaadin 10 and not start learning "old" Vaadin (even if it will be supported for years).

Use Vaadin 8

I'm developing with Vaadin for a couple of years and I would recommend to stick to Vaadin 8.

While there is a fundamental change on the horizon with Vaadin 10 (Replacement of GWT by WebComponents), I strongly suggest to stick with Vaadin 8 for starting a new project. Especially if you are also starting with Vaadin.

Vaadin 10 is a developer preview version. There will be a lot of changes along the way. Also the pool of knowledge (documentation, StackOverflow, Forum, etc.) is much much smaller. Also I don't see a stable release happening in 2018. My guess is summer 2019 till it is stable enough to replace Vaadin 8.

Read about the long-term plans for Vaadin 8 on the company’s roadmap. The plans include a regular quarterly release cadence for several years.

Update 2018 March: Vaadin 10 (now known as Vaadin Flow) just went into beta. And the company announced a new release cadence plan, with quarterly releases and Long-Term Support (LTS) releases. Maybe a stable release will happen sooner than I expected. But I still recommend Vaadin Framework 8 for a new project.

Consider Vaadin 14

Update 2019 August: Vaadin 14, the current LTS version, is now released.

If your users will be using recent versions of the modern “evergreen” web browsers, if starting a new project, and if the components you need are available, then Yes I recommend trying 14. Beware of this speed bump I encountered and resolved when getting started with a new Vaadin 14 project.

I've made this modified version of the Beverage Buddy app starter you can check out: https://github.com/OlliTietavainenVaadin/drink-starter-flow. Only Java used there, no CSS or JavaScript.

Edit (01/2020): this is probably no longer a good idea to use, you should go with Vaadin 14 instead.