Failed to load the bootstrap javascript: ./VAADIN/vaadinBootstrap.js?v=7.7.

I have a problem with my web app.
After reboot my centos server, my web app is blank on browser and view on “view source”:
Failed to load the bootstrap javascript: ./VAADIN/vaadinBootstrap.js?v=7.7.6.
My serlvet class is

package it.phebo.evoadmin.servlet;

import javax.servlet.annotation.WebServlet;

import com.vaadin.spring.server.SpringVaadinServlet;

@WebServlet(urlPatterns = “/*”, name = “EvoAdminVaadinServlet”, asyncSupported = true)
public class EvoAdminVaadinServlet extends SpringVaadinServlet {

private static final long serialVersionUID = 3951183995354995516L;


and web.xml is:

<?xml version="1.0" encoding="UTF-8"?>



Have you check your Spring Security configuration, I have below some sample about what specific things needs to be added with Vaadin. I suspect especially that reg = reg.antMatchers("/VAADIN/**").permitAll(); is missing, and hence Spring Security blocks Browser to access that file and you get 404.

protected void configure(HttpSecurity http) throws Exception {
	// Not using Spring CSRF here to be able to use plain HTML for the login
	// page


	// Allow access to static resources ("/VAADIN/**")
	reg = reg.antMatchers("/VAADIN/**").permitAll();
	// Require authentication for all URLS ("/**")
	reg = reg.antMatchers("/**").hasAnyAuthority(Role.getAllRoles());
	HttpSecurity sec = reg.and();

Reg is not declarate in your example