Return JSON for ResponseEntity<String>

Question

I have a method in my controller that should returns a String in JSON. It returns JSON for non primitive types:

@RequestMapping(value = "so", method = RequestMethod.GET, 
    produces = MediaType.APPLICATION_JSON_VALUE)
ResponseEntity<String> so() {
    return new ResponseEntity<String>("This is a String", HttpStatus.OK);
}

The curl response is:

This is a String

Answer 1

@RequestMapping(value = "so", method = RequestMethod.GET, produces = MediaType.APPLICATION_JSON_VALUE)
public @ResponseBody String so() {
    return "This is a String";
}