Generally the problem is that: when you annotate an @feignclient interface with @requestmapping annotation the handler will be also registered within Spring MVC.

Example:

@FeignClient("localapp")

@RequestMapping(value = "/users")

public interface UsersClient extends CrudClient<User> {


}

In this test case: jmnarloch/spring-cloud-netflix@2d24bf6 this acctually causes the test to fail with error:

Caused by: java.lang.IllegalStateException: Ambiguous mapping. Cannot map 'feignHttpClientTests$UserClient' method 
public abstract T org.springframework.cloud.netflix.feign.valid.FeignHttpClientTests$CrudClient.get(long)
to {[/users/{id}],methods=[GET]}: There is already 'feignHttpClientTests.Application' bean method
public java.lang.Object org.springframework.cloud.netflix.feign.valid.FeignHttpClientTests$Application.get(long) mapped.
    at org.springframework.web.servlet.handler.AbstractHandlerMethodMapping$MappingRegistry.assertUniqueMethodMapping(AbstractHandlerMethodMapping.java:565)
    at org.springframework.web.servlet.handler.AbstractHandlerMethodMapping$MappingRegistry.register(AbstractHandlerMethodMapping.java:529)
    at org.springframework.web.servlet.handler.AbstractHandlerMethodMapping.registerHandlerMethod(AbstractHandlerMethodMapping.java:252)
    at org.springframework.web.servlet.handler.AbstractHandlerMethodMapping.detectHandlerMethods(AbstractHandlerMethodMapping.java:223)
    at org.springframework.web.servlet.handler.AbstractHandlerMethodMapping.initHandlerMethods(AbstractHandlerMethodMapping.java:183)
    at org.springframework.web.servlet.handler.AbstractHandlerMethodMapping.afterPropertiesSet(AbstractHandlerMethodMapping.java:164)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping.afterPropertiesSet(RequestMappingHandlerMapping.java:134)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1637)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1574)
    ... 44 more

Due to duplicated Spring MVC - FeignClient mappings, but this how I found this issue.

Removing the top @requestmapping fixes the tests, but disallows some advances usages like interface inheritance and path overriding.

What about doing:

@Configuration
@ConditionalOnClass({Feign.class})
public class FeignMappingDefaultConfiguration {
    @Bean
    public WebMvcRegistrations feignWebRegistrations() {
        return new WebMvcRegistrationsAdapter() {
            @Override
            public RequestMappingHandlerMapping getRequestMappingHandlerMapping() {
                return new FeignFilterRequestMappingHandlerMapping();
            }
        };
    }

    private static class FeignFilterRequestMappingHandlerMapping extends RequestMappingHandlerMapping {
        @Override
        protected boolean isHandler(Class<?> beanType) {
            return super.isHandler(beanType) && (AnnotationUtils.findAnnotation(beanType, FeignClient.class) == null);
        }
    }
}