Documentation versions (currently viewingVaadin 24)

Converting Legacy UIs

The UI object — which represents the <body> element in the page — is controlled by Flow when running the MPR. As a result, anything extending UI should be converted. Actually, UI class shouldn’t be used for layout or navigation handling. At the end of this part of the process, you shouldn’t have any UI class — unless you have a real use case for it.

Depending on what’s used in the project, you have several conversion paths:

  • Application uses Spring Boot

  • Application uses CDI

  • Application uses Navigator

  • Application doesn’t use any of those.

Continue to Converting a UI.