I fixed the error by commenting out an important artifact in pom.xml, launching the service (aborting because of errors), then adding the artifact again.
It was this artifact:
There are default Grid renderers (like NumberRenderer and DateRenderer), but the ones in the Grid Renderers Collection are still in an add-on. Note that you’ll want a more recent version of the add-on for Vaadin 8, probably 2.2.10.
When I add the addon with version 2.2.10, i get “Failed to load the widgetset: ./…/…/VAADIN/widgetsets/AppWidgetset/AppWidgetset.nocache.js?1519133143113” error again.
Peter Schäfer:
When I add the addon with version 2.2.10, i get “Failed to load the widgetset: ./…/…/VAADIN/widgetsets/AppWidgetset/AppWidgetset.nocache.js?1519133143113” error again.
Are there any widgetset compilations errors in your maven build log?