Vaadin DeploymentConfiguration Servlet Init Parameters

The official Vaadin documentation on configuration properties is quite well hidden, therefore I’ll repost it here. In order to change DeploymentConfiguration properties, pass them as a servlet init parameter. Simply define your own servlet which extends VaadinServlet:

@WebServlet(urlPatterns = "/*", name = "myservlet", asyncSupported = true, initParams = {@WebInitParam(name = InitParameters.SERVLET_PARAMETER_CLOSE_IDLE_SESSIONS, value = "true")})
public class MyServlet extends VaadinServlet {
}

To check whether the configuration was applied, call the following e.g. from your main route:

@Route("")
public class MainView extends VerticalLayout {

    public MainView() {
        System.out.println(VaadinServlet.getCurrent()); // to verify that the servlet class is MyServlet
        System.out.println(VaadinService.getCurrent().getDeploymentConfiguration().isCloseIdleSessions()); // should print "true"
    }
}

Written on August 19, 2022