JAVA - Spring NullPointerException

Question

Would you be so kind and help me with this piece of code? I got NullPointerException. I have tried lot of stuffs without success. I am trying to fetch data from open API to RestTemplate. At this point i would be happy even for output to console. So i am trying to write Astronauts to console in my AstroController.

//EDIT: Anotation @Autowired added, still i am getting empty list (during debuging)

Thank you for your help, Ondrej

AstroService

package com.example.mydemo.service;

import com.example.mydemo.model.AstroResult;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.web.client.RestTemplateBuilder;
import org.springframework.stereotype.Service;
import org.springframework.web.client.RestTemplate;

@Service
public class AstroService {
    private final RestTemplate restTemplate;
    
     @Autowired
     public AstroService(RestTemplateBuilder rtBuilder) {
         restTemplate = rtBuilder.build();
     }

    public AstroResult getAstronauts(){
        String url = "http://api.open-notify.org/astros.json";
        return restTemplate.getForObject(url, AstroResult.class);

    }
}

AstroController

package com.example.mydemo.controller;

import com.example.mydemo.model.Astronaut;
import com.example.mydemo.service.AstroService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;

@RestController
public class AstroController {
    @Autowired
    private AstroService astroService;

    @GetMapping("/astronauts")
    void getListOfAstronauts (){
        List<Astronaut> list = astroService.getAstronauts().getAstronautList();
        for (Astronaut astronaut : list) {
            System.out.printf(astronaut.getName());
        }
    }
}

Astro (model)

    package com.example.mydemo.model;

    import lombok.AllArgsConstructor;
    import lombok.Getter;
    import lombok.NoArgsConstructor;
    import lombok.Setter;
    
    @Getter @AllArgsConstructor @NoArgsConstructor @Setter
    public class Astronaut {
    
        private String name;
        private String craft;
    
    }

AstroResult (model)

    package com.example.mydemo.model;
    
    import lombok.AllArgsConstructor;
    import lombok.Getter;
    import lombok.NoArgsConstructor;
    import lombok.Setter;
    
    import java.util.List;
    
    @Getter
    @AllArgsConstructor
    @NoArgsConstructor
    @Setter
    public class AstroResult {
        private String message;
        private int number;
        private List<Astronaut> astronautList;
    }

AstroServiceTest

package com.example.mydemo;

import com.example.mydemo.model.AstroResult;
import com.example.mydemo.model.Astronaut;
import com.example.mydemo.service.AstroService;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;

import java.util.List;

import static org.junit.jupiter.api.Assertions.*;

@SpringBootTest
public class AstroServiceTest {
    @Autowired
    private AstroService astroService;

    @Test
    void getAstronauts() {
        AstroResult astroResult = astroService.getAstronauts();
        int count = astroResult.getNumber();
        System.out.printf("There are: " + count + " people in space.");
        List<Astronaut> astroResultList = astroResult.getAstronautList();
        astroResultList.forEach(System.out::println);
        assertAll(
                () -> assertTrue(count > 0),
                () -> assertEquals(count, astroResultList.size())
        );
    }
}