Как сконфигурировать Spring через java-based и WebMvcConfigurer?

package com.example.config;
 
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.ViewResolver;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.ViewControllerRegistry;
import org.springframework.web.servlet.config.annotation.ViewResolverRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
import org.springframework.web.servlet.view.InternalResourceViewResolver;
import org.springframework.web.servlet.view.JstlView;
 
@Configuration
@ComponentScan("com.example")
@EnableWebMvc
public class SpringConfig implements WebMvcConfigurer {
    @Override
    public void addViewControllers(ViewControllerRegistry registry) {
        registry.addViewController("/").setViewName("index");
    }
 
    @Bean
    public ViewResolver viewResolver() {
        InternalResourceViewResolver bean = new InternalResourceViewResolver();
 
        bean.setViewClass(JstlView.class);
        bean.setPrefix("/WEB-INF/Views/");
        bean.setSuffix(".jsp");
 
        return bean;
    }
}

package com.example.config;
 
import org.springframework.web.WebApplicationInitializer;
import org.springframework.web.context.ContextLoaderListener;
import org.springframework.web.context.support.AnnotationConfigWebApplicationContext;
import org.springframework.web.context.support.GenericWebApplicationContext;
import org.springframework.web.servlet.DispatcherServlet;
 
import javax.servlet.ServletContext;
import javax.servlet.ServletRegistration;
 
public class MySpringMvcDispatcherServletInitializer implements WebApplicationInitializer {
    @Override
    public void onStartup(final ServletContext sc) {
 
        AnnotationConfigWebApplicationContext root = new AnnotationConfigWebApplicationContext();
 
        root.scan("com.example");
        sc.addListener(new ContextLoaderListener(root));
 
        ServletRegistration.Dynamic appServlet = sc.addServlet("mvc", new DispatcherServlet(new GenericWebApplicationContext()));
        appServlet.setLoadOnStartup(1);
        appServlet.addMapping("/");
    }
}

package com.example.controllers;
 
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
 
@Controller
public class SampleController {
    @GetMapping("/sample")
    public String showForm() {
        return "index";
    }
}