Spring RESTful web-service returns 404 AFTER url is successfully called

Question

I have a Spring MVC 4 app with Spring Security 4 and is deployed on Tomcat 8 running under jdk 1.8. The web-service has the controller defined as such:

@RequestMapping(value = "/build", method = RequestMethod.POST, produces = "application/json", headers =
{ "Accept=*/*", "Content-Type=*/*" })
public SubjectEntity build(@RequestBody SubjectImportDTO subjectImportDTO)
{
    Object principal = SecurityContextHolder.getContext().getAuthentication().getPrincipal();
    User user = null;
    if (principal instanceof User)
    {
        user = ((User) principal);
    }
    SubjectEntity entity = service.build(subjectImportDTO);
    System.out.println("FINISH: build");
    return entity;
}

I am getting a csrf token, I have that setup correctly. I know the url is getting called correctly because I can see that in the logs when I get there. The service on the back-end is running, data is correctly entered into the database, I correctly get the write object, and using the Jackson Mapper, the object 'SubjectEntity' should be translated into JSON and sent back to the requesting client. This web-service has been unit tested under the Spring Web Test framework, and it works great!

So, I am familiar with an HTTP 404 error in not finding a URL when the wrong parameters are passed in, or you're trying to do a POST when it's a GET, etc. So many reasons why we can get a 404 error ...

BUT ... IN THIS CASE ... We've already gotten to the URL, executed the code, and then it has the data it needs. Since the Controller says we have content-type / and it produces application/json, I don't know what else could be wrong?

Any ideas?

Answer 1

You should add @ResponseBodyto your method. without this, Spring mvc tries to find another handler method which can send a response.

NB: @RestController automatically add @ResponseBody on each method in a controller.