WebConfig.java

@Configuration
@EnableWebMvc
public class WebConfig implements WebMvcConfigurer {
    //register custom formatters and converters
    @Override
    public void addFormatters(FormatterRegistry registry) {
        // ...
    }

   //customize global Validator instance
	//If you need to have a LocalValidatorFactoryBean injected somewhere, create a bean and mark it with @Primary in order to avoid conflict with the one declared in the MVC configuration.
	@Override
	public Validator getValidator() { ... }

	//register Validator implementations locally
	@InitBinder
	protected void initBinder(WebDataBinder binder) {
		binder.addValidators(new FooValidator());
	}

	// register custom interceptors	
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(new LocaleChangeInterceptor());
        registry.addInterceptor(new ThemeChangeInterceptor()).addPathPatterns("/**").excludePathPatterns("/admin/**");
        registry.addInterceptor(new SecurityInterceptor()).addPathPatterns("/secure/*");
    }

	@Override public void configureContentNegotiation(ContentNegotiationConfigurer configurer) {
		configurer.mediaType("json", MediaType.APPLICATION_JSON);
		configurer.mediaType("xml", MediaType.APPLICATION_XML);
	}

	//forward a request to / to a view called home
	//this is the equivalent of registering a ParameterizableViewController
	@Override
	public void addViewControllers(ViewControllerRegistry registry) {
		registry.addViewController("/").setViewName("home");
	}
 
	//configure message converters
	@Override
  public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
      Jackson2ObjectMapperBuilder builder = new Jackson2ObjectMapperBuilder()
              .indentOutput(true)
              .dateFormat(new SimpleDateFormat("yyyy-MM-dd"))
              .modulesToInstall(new ParameterNamesModule());
      converters.add(new MappingJackson2HttpMessageConverter(builder.build()));
      converters.add(new MappingJackson2XmlHttpMessageConverter(builder.createXmlMapper(true).build()));
  }

	//configure the registration of view resolvers
	//this example configures content negotiation view resolution by using JSP and Jackson as a default View for JSON rendering
	@Override
  public void configureViewResolvers(ViewResolverRegistry registry) {
      registry.enableContentNegotiation(new MappingJackson2JsonView());
  registry.freeMarker.cache(false);
      registry.jsp();
  }

	// in Java-based configuration we can setup the according view template configurer as a bean
	@Bean
	public FreeMarkerConfigurer freeMarkerConfigurer() {
		FreeMarkerConfigurer configurer = new FreeMarkerConfigurer();
		configurer.setTemplateLoaderPath("/freemarker");
		return configurer;
	}

	//configure path matching
  @Override
  public void configurePathMatch(PathMatchConfigurer configurer) {
      configurer
          .setUseSuffixPatternMatch(true)
          .setUseTrailingSlashMatch(false)
          .setUseRegisteredSuffixPatternMatch(true)
          .setPathMatcher(antPathMatcher())
          .setUrlPathHelper(urlPathHelper())
          .addPathPrefix("/api",
                  HandlerTypePredicate.forAnnotation(RestController.class));
  }

  @Bean
  public UrlPathHelper urlPathHelper() {
      //...
  }

  @Bean
  public PathMatcher antPathMatcher() {
      //...
  }

	@Override
  public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {
      configurer.enable();
  //or pass a string to set the name of the default servlet name
  configurer.enable("myCustomDefaultServlet");
  }

  //static resources handling configuration
  @Override
  public void addResourceHandlers(ResourceHandlerRegistry registry) {
      registry.addResourceHandler("/resources/**")
    .addResourceLocations("/public/")
    .resourceChain(true)
    .setCachePeriod(86400)
    .addResolver(new VersionResourceResolver().addContentVersionStrategy("/**"));
  }

}