//starter
@SpringBootApplication
@EnableAsync
@EnableWebSecurity
public class Starter {
    public static void main(String[] args) {
        SpringApplication.run(Starter.class);
    }
}

//CONFIG
@Configuration
public class SecurityWebConfig extends WebSecurityConfigurerAdapter {
    @Override
    protected void configure(HttpSecurity http) throws Exception {
http.cors();
    }

}
// CONFIG
@Configuration
public class WebMvcConfig implements WebMvcConfigurer {
    @Override
    public void addCorsMappings(CorsRegistry registry) {
        registry.addMapping("/**").allowedOrigins("").allowedMethods("GET,POST");
    }

    @Bean
    public WebServerFactoryCustomizer<ConfigurableServletWebServerFactory> webServerFactoryCustomizer(){
     return container->{

       container.addErrorPages(new ErrorPage(HttpStatus.NOT_FOUND,"/index.html"));
     };
  }
}

//Controller
@GetMapping("/getAllMessages")
    public List<Message> getAllMessages() throws Exception{
        return messageService.getAllMessages();
    }