Version mismatch problems with custom widget sets are a common source of grief for many beginners in Vaadin. If you need add-ons or your own custom components that include widget sets, you of course need to compile them, but otherwise it is unnecessary.
If you do not use any such add-ons or your own custom components, do the following:
If you are using the Eclipse plugin, disable automatic widget set compilation from project preferences, in the Vaadin category, by selecting Suspend automatic widgetset builds. This prevents accidental compilation of the unnecessary widget sets. You may want to do this anyhow as the automatic builds can be annoying. You can still always build the widget set with the button in the toolbar.
Remove all widget set folders from under the
VAADIN/widgetsets
folder.
Edit the WEB-INF/web.xml
file and remove the
widgetset
init parameter from the servlet. It
looks as follows:
<init-param> <description>Application widgetset</description> <param-name>widgetset</param-name> <param-value>com.vaadin.demo.colorpicker.widgetset.ColorPickerWidgetSet</param-value> </init-param>
Refresh the project. In Eclipse, select the project and press F5, stop the server, clean the server temporary directories, and restart it.
At least in development environments, if you have extracted Vaadin themes to
the VAADIN/themes
folder, you should remove them and let
them be loaded dynamically from the Vaadin JAR.