Static initializer to start emebdded Jetty

App.java

public class App {
  static {
    new Thread(() -> {
      Server server = new Server(8080);

      ServletContextHandler context = new ServletContextHandler(ServletContextHandler.SESSIONS);
      context.setContextPath("/");
      server.setHandler(context);

      try {
        server.start();
        server.join();
      } catch (Exception e) {
        e.printStackTrace();
      }
    }).start();
  }
  //...
}