Hello,
I’ve discovered Vaadin a while ago, and today I have decided to experiment with it by myself (so far I liked what I’ve seen, reviews I found were also very good, so I’m seriously considering building my university graduation work on top of it 
)
Anyway, to get to the point:
I’ve installed Vaadin plugin into eclipse, installed Glassfish v3 server, configured Eclipse to work with Glassfish and created a ‘New Vaadin project’ via the Vaadin Eclipse plugin. Project created, it even created a sample demo application (supposed to write “Hello Vaadin user” on the screen). So I’ve decided to run it straight away, to test my first Vaadin application (well it’s not actually mine, but running on my own server 
)
However, I only get blank screen (but the wait animation icon is displayed for a second or two, then everything disappears)
This is web.xml file (although I didn’t change anything there)
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
<display-name>test</display-name>
<context-param>
<description>
Vaadin production mode</description>
<param-name>productionMode</param-name>
<param-value>false</param-value>
</context-param>
<servlet>
<servlet-name>Test Application</servlet-name>
<servlet-class>
com.vaadin.terminal.gwt.server.ApplicationServlet</servlet-class>
<init-param>
<description>
Vaadin application class to start</description>
<param-name>application</param-name>
<param-value>com.example.test.TestApplication</param-value>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>Test Application</servlet-name>
<url-pattern>/*</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.html</welcome-file>
<welcome-file>index.htm</welcome-file>
<welcome-file>index.jsp</welcome-file>
<welcome-file>default.html</welcome-file>
<welcome-file>default.htm</welcome-file>
<welcome-file>default.jsp</welcome-file>
</welcome-file-list>
</web-app>
Version of Vaadin plugin is 1.2.1.201003300626, version of Vaadin is 6.3.1