How to use treetable or calender add-ons related with widget?

Recently,we choose vaadin as our project’s framework.when I come to add-ons like treetable or calender,I come accross a same problem.I just only know download related jar,then put it in web-inf/lib,then complie vaadin widgets,finally run my project on my server.But it failed whatever I use treetable add-on or calender add-on,such as:

Requested resource [VAADIN/widgetsets/com.example.calendartest.widgetset.CalendartestWidgetset/com.example.calendartest.widgetset.CalendartestWidgetset.nocache.js]
not found from filesystem or through class loader. Add widgetset and/or theme JAR to your classpath or add files to WebContent/VAADIN folder.

Is there any key steps which I omit?I use eclipse +vaadin+tomcat,no other plugins.Is there any plugins I omit?
who would like to tell me how to run the addon like treetable or calender step by step,meanwhile I need not know the principle of widget ,I just only need to know how to apply it on my project .I need your help,thank you!


The most common reason for that problem is that the project is not refreshed after the new widgetset is compiled. To refresh the project select the project and press F5 (or right click and select Refresh from the context menu).

If that did not work you should look at what the widgetset compiler is doing. To get more info out of the widgetset compiler you need to set it in verbose mode. To do that right click on your project, select properties and select the Vaadin tab. In there you should check the “Verbose compilation output” checkbox. Now try to compile the widgetset again and check the console for errors.