Example Vaadin+Gwt+Liferay

I am trying to make a small example portlet in Liferay, but I try to integrate Gwt (Google Web Toolkit + Vaadin + Liferay)

a) I’ve installed Gwt plugin (from Web) in Eclipse. (It’s ok)
b) In project properties eclipse I have activate:
- Use Google app Engine → Use specific SDK (1.2.6)
- Use Google Web ToolKit → “” (1.7.1)
(Libraries are correct installed in project)

The example:

package com.example.mauro1;

import com.vaadin.Application;
import com.vaadin.ui.*;

import com.google.gwt.core.client.GWT;

public class Mauro1Application extends Application {
public void init() {
Window mainWindow = new Window(“Mauro1 Application”);
Label label = new Label(“Hello Mauro User”);

GWT.log(“Hello World!”, null);



c)In apache tomcat log: 1 portlet for Mauro-example is available for use
d) (Liferay) Add application The apache-tomcat log message say:

         17:45:09,342 ERROR [PortletRequestDispatcherImpl:316]

javax.servlet.ServletException: java.lang.NoClassDefFoundError: com/google/gwt/core/client/GWT
javax.servlet.ServletException: java.lang.NoClassDefFoundError: com/google/gwt/core/client/GWT
at com.vaadin.terminal.gwt.server.AbstractApplicationServlet.handleServiceException(AbstractApplicationServlet.java:828)
at com.vaadin.terminal.gwt.server.AbstractApplicationServlet.service(AbstractApplicationServlet.java:478)
etc …
etc …

How can I integrate in Liferay ?

Hi Mauro!

The GWT.log call in your application wont work, since the Application instance runs on the server (plain java, no GWT) and communicates with the user’s web browser that runs the GWT code. This is why the GWT class cannot be found on the server side.

Please see
the Book of Vaadin
for a more thorough explanation of the client/server architecture of Vaadin.