Time for action – separating business classes from UI classes
Vaadin is mostly about UI. Vaadin's motto thinking of U and I is not in vain. I said mostly because you can additionally find a bunch of useful add-ons to deal with server-side technologies. Even Vaadin itself ships with some data components.
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There are lots of integration add-ons for Vaadin. For instance, you can integrate with technologies such as Groovy, Spring Framework, SQL, JPA, Hibernate, Lucene, Google App Engine Datastore, Quartz, JasperReports, JFreeChart, OpenLayers, Google Maps, OpenID, and even Twitter! All this with one hand tied behind your back. Visit https://vaadin.com/directory.
Most, if not all, applications have some kind of business logic. That is, something to do with the application's data. If you are an experienced developer you will agree with me that separating business logic from UI logic makes a lot of sense. For the "Time It" application, we will use two Java packages to separate business logic from...