Difference between getRootConfigClasses and getServletConfigClasses

What fundamental difference is there in initializing the Spring configuration classes in getRootConfigClasses and getServletConfigClasses in the WebInitializer class ?

I have tried changing the initialization of my configuration classes in both methods without different results, the theory says that they are different contexts but both ways work the same.

I would like to know what the correct way is or if it represents any impact on my project to have it in one way or another.

    @Configuration
public class WebInitializer extends AbstractAnnotationConfigDispatcherServletInitializer{

    @Override
    protected Class<?>[] getRootConfigClasses() {
        return new Class<?>[]{SecurityConfig.class};
    }

    @Override
    protected Class<?>[] getServletConfigClasses() {
        return new Class<?>[]{WebConfig.class, SwaggerConfig.class};
    }

    @Override
    protected Filter[] getServletFilters() {
         return new Filter[] {new DelegatingFilterProxy("springSecurityFilterChain")};
    }

    @Override
    protected String[] getServletMappings() {
        return new String[]{"/"};
    }

}

It works the same way, for example:

 @Configuration
    public class WebInitializer extends AbstractAnnotationConfigDispatcherServletInitializer{

        @Override
        protected Class<?>[] getRootConfigClasses() {
            return new Class<?>[]{WebConfig.class, SecurityConfig.class,SwaggerConfig.class};
        }

        @Override
        protected Class<?>[] getServletConfigClasses() {
            return new Class<?>[]{};
        }

        @Override
        protected Filter[] getServletFilters() {
             return new Filter[] {new DelegatingFilterProxy("springSecurityFilterChain")};
        }

        @Override
        protected String[] getServletMappings() {
            return new String[]{"/"};
        }

    }