Java Project plus Vaadin Facet

I have been looking for this (see quoted thread below). I have a project which wouldn’t compile my widget set and therefore I couldn’t use some of the addons. I’m so glad I happened across this while browsing the forum.

However, after adding the “Vaadin Eclipse Integration” facet to my project and attempting to compile the widget set, I get the following, so there is still something I am missing:

Starting GWT compiler
Mar 30, 2011 10:17:14 AM$1 run
SEVERE: Widgetset compilation failed
	at Method)
	at java.lang.ClassLoader.loadClass(
	at sun.misc.Launcher$AppClassLoader.loadClass(
	at java.lang.ClassLoader.loadClass(
	at java.lang.Class.forName0(Native Method)
	at java.lang.Class.forName(

Do I need to include the gwt compiler explicitly, and if so, how do I go about doing so?

If it is something else, please feel free to point me in the right direction.



Quoted Thread:

The GWT JARs (gwt-user.jar and gwt-dev.jar) are automatically added to the project classpath (after downloading the correct versions for your Vaadin version, if necessary) when creating a Vaadin project or changing the Vaadin version in Project Properties → Vaadin.

Try to change to some other Vaadin version and then back on that tab. I hope that will help.

Otherwise, you can manually download the JARs and put them on your classpath, but then you have to know which versions are needed for your Vaadin version and upgrade them yourself when upgrading Vaadin.


Thanks for your help. I wasn’t able to change my Vaadin version in my properties. I’m not sure why. Possibly because I only have one version available in my Eclipse. Whatever the reason, the select was disabled and I couldn’t change it.

However, thanks to your post, I did know what I needed; the gwt jars. With the help of my supervisor (because I’m new to maven) we were able to add the appropriate dependencies in maven and get the jars.

The widgetset now compiles fine.


Hi all,

I had the same problem. Managed to get it working with dependecies… But I still cant figure out why is the Vaadin download button, disabled in Project properties->Vaadin.

If I make a new clean project, then it is ok?

Any ideas? Otherwise this is a maven project, and was imported as existing maven project to workspace, then the additional plugin Vaadin was installed.

with br