Spring MVC java config via AbstractAnnotationConfigDispatcherServletInitializer

Hi I have a strange problem,

I'am following this Tutorial (http://websystique.com/springmvc/spring-4-mvc-and-hibernate4-integration-example-using-annotations/) and at step 5, configurting initializer class there are two ways of doing that:

1 with WebAppInitializer (my code below)

public class SpindleSpringWebAppInitializer implements WebApplicationInitializer {

public void onStartup(ServletContext servletContext) throws ServletException {
    AnnotationConfigWebApplicationContext appContext = new AnnotationConfigWebApplicationContext();
    appContext.register(AppConfig.class);
    appContext.setServletContext(servletContext);

    ServletRegistration.Dynamic dispatcher = servletContext.addServlet(
            "SpringDispatcher", new DispatcherServlet(appContext));
    dispatcher.setLoadOnStartup(1);
    dispatcher.addMapping("/");

}

2. With AppInitializer extends AbstractAnnotationConfigDispatcherServletInitializer (my code here)

   public class AppInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {
   
   @Override
   protected Class<?>[] getRootConfigClasses() {
       return new Class[] { AppConfig.class };
   }
   
   @Override
   protected Class<?>[] getServletConfigClasses() {
       return null;
   }
   
   @Override
   protected String[] getServletMappings() {
       return new String[] { "/" };
   }
   
   }
   

This is my AppConfig.java

@Configuration
@EnableWebMvc
public class AppConfig extends WebMvcConfigurerAdapter{

    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry.addResourceHandler("/resources/**").addResourceLocations("/resources/").setCachePeriod(31556926);
    }


    @Bean
    public ViewResolver viewResolver() {
        InternalResourceViewResolver viewResolver = new InternalResourceViewResolver();
        viewResolver.setViewClass(JstlView.class);
        viewResolver.setPrefix("/WEB-INF/views/");
        viewResolver.setSuffix(".jsp");
        return viewResolver;
    }

    @Bean
    public MessageSource messageSource() {
        ResourceBundleMessageSource messageSource = new ResourceBundleMessageSource();
        messageSource.setBasename("messages");
        return messageSource;
    }
}

The Thing is that when I use the first method everything works, but when I use the second one i get 404 (description The requested resource is not available). I have no other errors and I have no idea how to debug this. I wouldn't bother but I'm trying to implement Spring Security to the code and as I understand the secon type of initializer is the preffered type nowdays.

I'm using Maven, STS, Pivotal tc Servert Developer Edition. Thanks for any feedback.