@org.springframework.boot.autoconfigure.AutoConfiguration(after = WebMvcAutoConfiguration.class)
@org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication(type = ConditionalOnWebApplication.Type.SERVLET)
@org.springframework.context.annotation.Import(GrailsWelcomePageAutoConfiguration.RemoveWelcomePageMappingRegistrar.class)
public class GrailsWelcomePageAutoConfiguration
extends java.lang.Object

Without the auto-injected @EnableWebMvc, Spring Boot's WebMvcAutoConfiguration is active and contributes a welcomePageHandlerMapping (and a welcomePageNotAcceptableHandlerMapping) that maps the root path ('/') to a static index.html found under classpath:/META-INF/resources/, classpath:/resources/, classpath:/static/ or classpath:/public/. In a Grails application the root path is expressed through UrlMappings, so this Boot convention overlaps with — and can shadow — the application's own '/' mapping whenever such an index.html happens to exist.

This removes both welcome-page handler mappings for every Grails servlet web application so that Grails' UrlMappings own the root path. Ordered after WebMvcAutoConfiguration so the bean definitions exist by the time the registrar runs.

Disable with grails.web.removeWelcomePageMapping=false to restore Boot's welcome-page behavior.