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Custom WidgetSet ClassCastException

David Norman
7 years ago Jun 16, 2015 11:53am

A little background first. I am writing a standalone application running on embedded jetty. It is not compiled as a war, but does deploy a WebContent folder with VAADIN and WEB-INF (with a web.xml for use in embedded jetty running alongside a guice container). Currently this is using vaadin 7.4.4 and Java 1.7. All other features are currently working in this configuration.

Right now, I want to add a custom renderer (call it for now a currency renderer). I cannot use the one present in the add-ons as that was built for 6.0 and I am taking the opportunity to figure out the under-the-covers items of vaadin/gwt. Based on the basics I know ...

  • created a CurrencyRenderer.java that extends import com.vaadin.ui.Grid.AbstractRenderer
  • created a CurrencyRendererWidgetset.gwt.xml with

   <inherits name="com.vaadin.DefaultWidgetSet" />
   <inherits name="com.google.gwt.resources.Resources" />

  • created a client component CurrencyRendererClient which inherits import com.vaadin.client.renderers.Renderer
  • created a connector class to put these all together

public class CurrencyRendererConnector extends AbstractRendererConnector<Currency> {
  public CurrencyRendererClient getRenderer() {
    return (CurrencyRendererClient) super.getRenderer();

  • compile the gwt widgetset, put into WebContent/VAADIN/widgetsets deployed
  • compile the jars and placed into WebContent/WEB-INF/lib

So, when I run this and try to use it in a vaadin grid, I get the following error (via Chrome javascript debugger, no error on the server):

Tue Jun 16 05:50:06 GMT-600 2015 com.vaadin.client.ApplicationConnection
SEVERE: Error sending state change eventscom.google.gwt.event.shared.UmbrellaException: Exception caught: undefined
    at Unknown.Eg(com.vaadin.DefaultWidgetSet-0.js)
    at Unknown.Ig(com.vaadin.DefaultWidgetSet-0.js)
    at Unknown.Og(com.vaadin.DefaultWidgetSet-0.js)
    at Unknown.Ex(com.vaadin.DefaultWidgetSet-0.js)
    at Unknown.Hx(com.vaadin.DefaultWidgetSet-0.js)
    at Unknown.cx(com.vaadin.DefaultWidgetSet-0.js)
    at Unknown.IAb(com.vaadin.DefaultWidgetSet-0.js)
    at Unknown.WAb(com.vaadin.DefaultWidgetSet-0.js)
    at Unknown.Ywb(com.vaadin.DefaultWidgetSet-0.js)
    at Unknown.Swb(com.vaadin.DefaultWidgetSet-0.js)
    at Unknown.cwb(com.vaadin.DefaultWidgetSet-0.js)
    at Unknown.awb(com.vaadin.DefaultWidgetSet-0.js)
    at Unknown.Dxb(com.vaadin.DefaultWidgetSet-0.js)
    at Unknown.Jx(com.vaadin.DefaultWidgetSet-0.js)
    at Unknown.ey(com.vaadin.DefaultWidgetSet-0.js)
    at Unknown.eval(com.vaadin.DefaultWidgetSet-0.js)
    at Unknown.li(com.vaadin.DefaultWidgetSet-0.js)
    at Unknown.oi(com.vaadin.DefaultWidgetSet-0.js)
    at Unknown.eval(com.vaadin.DefaultWidgetSet-0.js)
Caused by: java.lang.ClassCastException

Clearly I missed something in a step to create custom widgets, but I am not sure what. Anyone know or have a good custom widgetset guide? The vaadin one is missing some items about creating when not using the eclipse plugin.


Petar Petrov
7 years ago Jul 03, 2015 7:49am
Esau Betancourt
7 years ago Jul 21, 2015 4:00pm
David Norman
7 years ago Jul 21, 2015 4:02pm
Esau Betancourt
7 years ago Aug 20, 2015 8:14pm
Marius Reinwald
7 years ago Aug 21, 2015 12:11pm