Define main servlet for scalatra/jetty at build/runtime

Question

I have a scalatra server with Jetty embedded and the initialization code for the two is listed below, where HelloServlet is the main servlet to be loaded.

Is there a way I can set this servlet at build or runtime?
I prefer not to use XMLs for configuring as I would like these methods to add other hooks there (unless one can use both?)

Jetty Startup

public class ExampleServer {

    public static void main(String[] args) throws Exception {
        Server server = new Server();
        ServerConnector connector = new ServerConnector(server);
        connector.setPort(8080);
        server.setConnectors(new Connector[] { connector });
        ServletContextHandler context = new ServletContextHandler();
        context.setContextPath("/hello");
        context.addServlet(HelloServlet.class, "/"); // Can this be defined later??
        HandlerCollection handlers = new HandlerCollection();
        handlers.setHandlers(new Handler[] { context, new DefaultHandler() });
        server.setHandler(handlers);
        server.start();
        server.join();
    }
}

Scalatra Startup

class ScalatraBootstrap extends LifeCycle {
  override def init(context: ServletContext) {
    context.mount(new HelloServlet, "/*") // Can this be defined later??
  }
}