Non of the answers worked for me, so I've managed to do it like that:
HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.parseMediaType("your content type here"));
headers.set("Content-Disposition", "attachment; filename=fileName.jpg");
headers.setContentLength(fileContent.length);
return new ResponseEntity<>(fileContent, headers, HttpStatus.OK);
Setting Content-Disposition
header I was able to download the file with the @ResponseBody
annotation on my method.