Spring not accepting a POST parameter unless @RequestParam "required=false"

I am running a Spring 3.1.2 application. I have a RESTful servlet with a number of methods. The GET methods are working fantastic (`@PathVariables` matching, responses correctly marshalled to JSON or XML based on the Accept header, etc) 100% of the time. However the POST method is simply not working. After hours of messing around with converts and every other Spring aspect I could find (all tinkering reverted), I narrowed it do to the `required` field in `@RequestParam`. This is a simplified test method I've been using to investigate: ``` @RequestMapping (value = "/bogus", method = POST) public @ResponseBody PassResponse bogus ( @RequestParam (value = "test", required = false) String test) { // Just some handy garbage objects that marshal to JSON/XML UserResponse user = new UserResponse (); user.setName (test); AccountDetail detail = new AccountDetail (user,null); return new PassResponse (detail); } ``` required=false: everything works (parameter is received and interpreted). Exactly as I expect it to work required=true: (or not specified, since this is the default) I consistently get the message "MissingServletRequestParameterException: Required String parameter 'test' is not present" Client side view: required=true ``` Request URL:http://localhost:8080/internal-project/rest/bogus Request Method:POST Status Code:400 Bad Request Request Headersview source Accept:application/json Connection:keep-alive Content-Length:12 Host:localhost:8080 Request Payload test=LALALAA Response Headersview source Connection:close Content-Length:971 Content-Type:text/html;charset=utf-8 Date:Wed, 24 Oct 2012 18:41:05 GMT Server:Apache-Coyote/1.1 ``` required=false ``` Request URL:http://localhost:8080/internal-project/rest/bogus Request Method:POST Status Code:200 OK Request Headersview source Accept:application/json Connection:keep-alive Content-Length:12 Host:localhost:8080 Request Payload test=LALALAA Response Headersview source Content-Type:application/json;charset=UTF-8 Date:Wed, 24 Oct 2012 18:44:03 GMT Server:Apache-Coyote/1.1 Transfer-Encoding:chunked ``` It is the exact same test suite being run when toggling `required` and I can see the parameter is being passed. When the parameter is optional, Spring handles the it correctly. If anyone has run across this before or has any ideas I'd love to hear them. Marking the required parameter as optional, even if it works, is terrible self documentation even if I comment it. Plus the behavior is making me a little nervous. Hopefully I just screwed something up somewhere...