Incorrect Javadoc for WebMvcConfigurer#addInterceptors

[samarthrastogi]

Affects: <5.1.x, 5.0.x>

---

In spring 5.1.x also in 5.0.x, resourceHandlerMapping picks up interceptors configured for controllers only.

WebMvcConfigurationSupport.java

@Bean
@Nullable
public HandlerMapping resourceHandlerMapping() {
	Assert.state(this.applicationContext != null, "No ApplicationContext set");
	Assert.state(this.servletContext != null, "No ServletContext set");

	ResourceHandlerRegistry registry = new ResourceHandlerRegistry(this.applicationContext,
			this.servletContext, mvcContentNegotiationManager(), mvcUrlPathHelper());
	addResourceHandlers(registry);

	AbstractHandlerMapping handlerMapping = registry.getHandlerMapping();
	if (handlerMapping == null) {
		return null;
	}
	handlerMapping.setPathMatcher(mvcPathMatcher());
	handlerMapping.setUrlPathHelper(mvcUrlPathHelper());
	handlerMapping.setInterceptors(getInterceptors()); // ==> here it adds all configured interceptors even those which are for controllers only.
	handlerMapping.setCorsConfigurations(getCorsConfigurations());
	return handlerMapping;
}

As per documentation of WebMvcConfigurer

	/**
	 * Add Spring MVC lifecycle interceptors for pre- and post-processing of
	 * controller method invocations. Interceptors can be registered to apply
	 * to all requests or be limited to a subset of URL patterns.
	 * <p><strong>Note</strong> that interceptors registered here only apply to
	 * controllers and not to resource handler requests. To intercept requests for
	 * static resources either declare a
	 * {@link org.springframework.web.servlet.handler.MappedInterceptor MappedInterceptor}
	 * bean or switch to advanced configuration mode by extending
	 * {@link org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport
	 * WebMvcConfigurationSupport} and then override {@code resourceHandlerMapping}.
	 */
	default void addInterceptors(InterceptorRegistry registry) {
	}

So any interceptor added using addInterceptors in WebMvcConfigurerAdapter or WebMvcConfigurer should not apply to resource handlerMapping which is not happening anymore.

[bclozel]

This has been the case since #20583.
Let’s use this issue to update the outdated javadoc.