Custom compnent composite not successfull with me

Iam creating a gui for my application using the vaadin WYSIWYG editor but unfortunately i cant run at all.
iam creating a vaadin project which by default create a java file that extends application then i create a “vaadin custom component (composite )” file that give me the code and design panels i start put my inputs till the needed gui completes after that i cant run it.

By default if i run the application i will see the "hello vaadin user " page i go to web.xml to change the path of the servlet to call my gui file i get " cannot be cast to com.vaadin.Application "

i have gone into alot of examples and in the forum i cant solve this problem at all , i really need your help on how to run files that i made on the WYSIWYG editor .

Secondly is there is any solutions to integrate GWT designer to vaadin or any java gui designer with vaadin.
Appreciate your help.

The WYSIWYG editor creates a component, not an application. You should still have your separate application class that creates a main window and adds your component to it.

Note that the editor is currently under work, and a new beta version should come out this summer.

As for other visual UI design tools - there is currently no support or integration, and for many of them, it is not clear if such support would be meaningful. However, you might be able to use GWT design tools within the client side parts of Vaadin widgets.

Thanks for your reply.

You should still have your separate application class that creates a main window and adds your component to it.

How i can do that???

all i want to see is the forms i create in WYSIWYG editor i just don’t know how.

Eclipse created you the application class when creating the project.

Just change the reference you modified in web.xml to point back to it (e.g. using “Replace with → from local history”), and change the application class so that you add a new instance of your visually composed class to the main window instead of adding a label.

how to make that instance i dont know how to make that reflection , i feel close to reach.
Henry iam very thankful for your help

Failed to load.
what i did is i make on the application file Window mainWindow = new Window("Inputs",new SplitPanel());
inputes is the file i create in the WYSIWYG editor , i also redirect the web.xml to call the application file but i cant still see the components i create:(

It seems it is easier to show an example than to explain:

package com.example.vetest;

import com.vaadin.Application;
import com.vaadin.ui.Window;

public class TestApplication extends Application {
    public void init() {
        Window mainWindow = new Window("Test Application");
        MyComponent myComponent = new MyComponent();
        // may be needed if you haven't set the size in the component
        // make sure the implicit layout of the main window fills the window

You could try to add “?debug” to your URL and then click “Analyze layouts”, which can provide useful information about some layout problems.

I would recommend watching the video on
, which covers creation of an application, custom component creation with the visual editor and much more.

thank you so much henri for your example , it is the one which solve my problem not the video.
Thanks to vaadin that have guys like you.