Request to the endpoint fails with the following error:
400 Bad request org.springframework.http.converter.HttpMessageNotReadableException: Requir
I met the similar problem today in spring-webmvc 5.1.5 and checked the library code. The HttpMessageNotReadableException was thrown from RequestResponseBodyMethodProcessor.readWithMessageConverters since it invoked readWithMessageConverters and got null. There is an loop in readWithMessageConverters searching suitable converter for the request Content-Type (for (HttpMessageConverter> converter : this.messageConverters)), and because I didn't specify and Content-Type in request, it failed.
So I specified the header Content-Type: application/json and solved the problem.