Error while trying to use post metod in springboot

I’m learning Spring Boot rn and I’m getting errors on my way when I’m trying to use POST method.

HTTP code is 400.

That’s the error:

Here is the code of my rest controller c:

package com.example.carsapi;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;

import java.awt.*;
import java.util.Optional;

@RestController
@RequestMapping("/cars")
public class CarRestController {

    private final CarService carService;

    @Autowired
    public CarRestController(CarService carService) {
        this.carService = carService;
    }

    @GetMapping
    public ResponseEntity<List> getCars(){
        return new ResponseEntity(carService.findAllCars(), HttpStatus.OK);
    }

    @GetMapping(value = "/id/{id}")
    public ResponseEntity<List> getCarById(@PathVariable Integer id){
        Optional<CarDTO> found = carService.findAllCars().stream().filter(car -> car.getCarId() == id).findFirst();
        if(found.isPresent()){
            return new ResponseEntity(found.get(), HttpStatus.OK);
        } else {
            return new ResponseEntity(HttpStatus.NOT_FOUND);
        }
    }

    @GetMapping(value = "/color/{color}")
    public ResponseEntity<List> getCarByColor(@PathVariable String color){
        Optional<CarDTO> found = carService.findAllCars().stream().filter(car -> car.getColor().equals(color)).findFirst();
        if(found.isPresent()){
            return new ResponseEntity(found.get(), HttpStatus.OK);
        } else {
            return new ResponseEntity(HttpStatus.NOT_FOUND);
        }
    }

    @PostMapping(value = "/add")
    public ResponseEntity addCar(@RequestBody CarDTO car){
        carService.findAllCars().add(car);
        return new ResponseEntity(HttpStatus.CREATED);
    }
}

And there is my JSON code which I’m using:

[ 
    {
        "carId": 3,
        "carBrand": "Audi",
        "carModel": "RS6",
        "color": "red"
    }
]

Hope you’ll help me I had even tried with @RequestParam, getting all of the values like id, brand, model and color and then adding a new object with these values which I’ve got from the query but it still didn’t work.

>Solution :

The request is an array while CarDTO is a single object. You can make the request with a body like this(notice the absence of []):

{
    "carId": 3,
    "carBrand": "Audi",
    "carModel": "RS6",
    "color": "red"
}