Hi, Instead of dealing with response decorators you could use org.apache.wicket.markup.html.IHeaderContributor
getHeaderContributorListeners().add( return response -> { response.render(CssHeaderItem.forReference(css1)); response.render(CssHeaderItem.forReference(css2)); }) IHeaderResponseDecorator is more powerful. It should be used when you want to intercept all header contributions and add/modify/remove contributions. On Wed, Sep 8, 2021 at 6:47 AM Arunachalam Sibisakkaravarthi < arunacha...@mcruncher.com> wrote: > Hi guys, > I am doing Wicket migration from 7.x to 9.x > In Wicket7.x I add css resource as below, it was working > > getHeaderResponseDecorators().add(getHeaderResponseDecorator()); > > private IHeaderResponseDecorator getHeaderResponseDecorator() > { > return response -> { > response.render(CssHeaderItem.forReference(css1)); > > response.render(CssHeaderItem.forReference(css2)); > > return new JavaScriptFilteredIntoFooterHeaderResponse(response, "scripts"); > }; > > whereas the above one doesn't work in Wicket9.x > Is there any alternative to css and js in init() method of WebApplication? > so that css/js will be available to all components. > > > > *Thanks And RegardsSibi.ArunachalammCruncher* >