due to a different startup sequence between a classic webserver and a spring boot app the configuration of servlets/filters currently fails during startup
This happens for CometAsyncServlet and WebSocketFilter.

With CometAsyncServlet it is possible to prevent ZK from initializing by setting a context attribute during ServletContextInitializer#onStartup:

@SpringBootApplication
public class Application implements ServletContextInitializer {
    @Override
    public void onStartup(ServletContext servletContext) throws ServletException {
        //required to avoid duplicate installing of the CometAsyncServlet
        //startup sequence in spring boot is different to a normal servlet webapp
        servletContext.setAttribute("org.zkoss.zkmax.ui.comet.async.installed", true);
        //servletContext.setAttribute("org.zkoss.zkmax.websocket.filter.installed", true);
    }

If something similar was awailable for the WebSocketFilter it would greatly simplify the current Spring boot integration prototype.

In the long run it would be nice if there was no such problem at all and servlets/filters are configured with standard config files, e.g. web-fragment or in web.xml