RETROFIT2 Can not deserialize instance of java.util.ArrayList out of START_OBJECT token

Question

I have some troubles with my call. My callback always return onFailure with this error:

onResponse: com.fasterxml.jackson.databind.JsonMappingException: Can not deserialize instance of java.util.ArrayList out of START_OBJECT token at [Source: okhttp3.ResponseBody$BomAwareReader@4c32516; line: 1, column: 1]

The API Response farms/abstract (with one item on list):

[
    {
        "id": "0fb30c45-00d9-4171-9673-85991dca5db2",
        "name": "Areado"
    }
]

This is my Interface:

public interface FarmService {

    @GET("farms/abstract")
    Call<ArrayList<FarmList>> getFarmList(@Header("Authorization") String token);
}

And this is my method/function:

private void callGetFarmList() {
        try {
            Call<ArrayList<FarmList>> call = new RetrofitConfig().getFarmList().getFarmList(authToken);
            call.enqueue(new Callback<ArrayList<FarmList>>() {
                @Override
                public void onResponse(@NonNull Call<ArrayList<FarmList>> call, @NonNull Response<ArrayList<FarmList>> response) {
                    if (response.isSuccessful()) {
                        if (response.body() != null) {

                            int codeResult = response.code();

                            switch (codeResult) {
                                case 200:
                                    farmListArrayList = new ArrayList<FarmList>();
                                    farmListArrayList = response.body();
                                    createFarmRecyclerView();
                                    break;
                                case 201:
                                    /*Created*/
                                    Log.d("201", "onResponse: 201");
                                    break;
                                case 401:
                                    /*Unauthorized*/

                                    break;
                                case 403:
                                    /*Forbidden*/

                                    break;
                                case 404:
                                    /*Error*/

                                    break;
                                default:
                                    break;
                            }
                        }
                    } else {
                        //Error
                    }
                }

                @Override
                public void onFailure(@NonNull Call<ArrayList<FarmList>> call, @NonNull Throwable t) {
                    Toast.makeText(FazendaActivity.this, "OK", Toast.LENGTH_SHORT).show();
                    Log.d("getFarmList", "onResponse: " + t);
                }
            });
        } catch (Exception e) {
            Log.d("erroGetFarmList", "callGetFarmList: " + e);
        }
    }

UPDATED

This is my class:

public class FarmList {
    @SerializedName("id")
    @Expose
    private String id;
    @SerializedName("name")
    @Expose
    private String name;

    public FarmList() {
        super();
    }

    public FarmList(String id, String name) {
        this.id = id;
        this.name = name;
    }

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    @Override
    public String toString() {
        return "FarmList{" +
                "id='" + id + '\'' +
                ", name='" + name + '\'' +
                '}';
    }
}

UPDATED 25/05/2020

I changed to GsonConverterFactory instead JacksonConverterFactory

public class RetrofitConfig {
    private final Retrofit retrofit;

    public RetrofitConfig() {
        this.retrofit = new Retrofit.Builder()
                .baseUrl("MY_BASE_URL")
                .addConverterFactory(GsonConverterFactory.create())
                .build();
    }

    public LoginService getLogin() {
        return this.retrofit.create(LoginService.class);
    }

    public FarmService getFarm() {
        return this.retrofit.create(FarmService.class);
    }

    public FarmService getFarmList() {
        return this.retrofit.create(FarmService.class);
    }
}

FINAL SOLUTION The BE send me a new response and now it's working like a charm. But thanks @KasımÖzdemir, for the time to help me

{
    "farms": [
        {
            "id": "0fc2b30c-4500-c399-4171-e2809373e280",
            "name": "Areado"
        },
        {
            "id": "81041a28-1193-4310-b616-fabcabdf63d7",
            "name": "Fazenda 3"
        }
    ]
}

@KasımÖzdemir the answer in the other topic is nice, but not solved my problem. This method (farms/abstract) return a farm list, my coworker use the list on iOS and fucntion normal. — Gabriel Júnior de Souza, May 22 '20 at 15:08
You can respond String instead of ArrayList>. Are you using GsonConverterFactory in RetrofitService? — Kasım Özdemir, May 22 '20 at 20:54
@KasımÖzdemir I'm using JacksonConverterFactory. Only String or a ArrayList? — Gabriel Júnior de Souza, May 25 '20 at 15:07
@KasımÖzdemir I changed to GsonConverterFactory instead JacksonConverterFactory and removed the ArrayList, put only the Object (FarmList) and now my response is successefull but my response.body() is null in both parameters (id, name). You know why? — Gabriel Júnior de Souza, May 25 '20 at 15:22
@KasımÖzdemir Because if I pass like a ArrayList, the response (throwable) is: java.lang.IllegalStateException: Expected BEGIN_ARRAY but was BEGIN_OBJECT at line 1 column 2 path $ — Gabriel Júnior de Souza, May 25 '20 at 15:47
You can try to use string instead ArrayList. Then you can convert string to ArrayList using GSON. — Kasım Özdemir, May 25 '20 at 15:54
Everyone used List instead ArrayList. You can look at [one](https://medium.com/@dds861/json-arrays-parsing-using-retrofit-and-recycleview-9b2d494cc24c) and [two](https://stackoverflow.com/questions/42623437/parse-json-array-response-using-retrofit-gson) — Kasım Özdemir, May 25 '20 at 16:43
Let us [continue this discussion in chat](https://chat.stackoverflow.com/rooms/214600/discussion-between-gabriel-junior-de-souza-and-kasim-ozdemir). — Gabriel Júnior de Souza, May 25 '20 at 16:48

RETROFIT2 Can not deserialize instance of java.util.ArrayList out of START_OBJECT token

0 Answers0