Return HTTP code 200 from Spring REST API

If you use @RestController it should return 200 by default.

But anyway, you can set a particular response status by @ResponseStatus annotation (even if the methods returns void) or you can return a custom response by ResponseEntity.

EDIT: added error handling

For error handling, you can return a particular response entity:

 return ResponseEntity.status(HttpStatus.FORBIDDEN)
            .body("some body ");

or you can use @ExceptionHandler:

   @ExceptionHandler(Exception.class)
    @ResponseStatus(HttpStatus.INTERNAL_SERVER_ERROR)
    public void handleError(Exception ex) {
        // TODO: log exception
    }

If you are using spring:

@PostMapping(value = "/v1/notification")
public ResponseEntity handleNotifications(@RequestParam("notification") String itemid) {
    // parse here the values
    return ResponseEntity.ok().build(); 
    //OR ResponseEntity.ok("body goes here");
}