Retrofit: Unable to create @Body converter for class

Question

I need to send next json via retrofit 2:

{
    "Inspection": {
        "UUID": "name",
        "ModifiedTime": "2016-03-09T01:13",
        "CreatedTime": "2016-03-09T01:13",
        "ReviewedWith": "name2",
        "Type": 1,
        "Project": {
            "Id": 41
        },
        "ActionTypes": [1]
    }   
}

With Header: Authorization: access_token_value

I tried this:

//header parameter
String accessToken = Requests.getAccessToken();

JsonObject obj = new JsonObject();
JsonObject inspection = new JsonObject();

inspection.addProperty("UUID","name");
inspection.addProperty("ModifiedTime","2016-03-09T01:13");
inspection.addProperty("CreatedTime","2016-03-09T01:13");
inspection.addProperty("ReviewedWith","name2");
inspection.addProperty("Type","1");

JsonObject project = new JsonObject();
project.addProperty("Id", 41);

inspection.add("Project", project);
obj.add("Inspection", inspection);

Retrofit restAdapter = new Retrofit.Builder()
        .baseUrl(Constants.ROOT_API_URL)
        .addConverterFactory(GsonConverterFactory.create())
        .addConverterFactory(ScalarsConverterFactory.create())
        .build();
IConstructSecureAPI service = restAdapter.create(IConstructSecureAPI.class);
Call<JsonElement> result = service.addInspection(accessToken, obj);
JsonElement element = result.execute().body();

But everytime i recieved exception: java.lang.IllegalArgumentException: Unable to create @Body converter for class com.google.gson.JsonObject (parameter #2)

How can I send it ? Or any another idea how I can do it. You can even offer me with parameter as simple String with json inside. It will suit for me

Please post IConstructSecureAPI just to know how are you building your request. — Darien Alvarez, Mar 09 '16 at 03:33

score 29 · Accepted Answer · answered Sep 14 '16 at 00:17

29

Solution: declare body value in your interface with next:

@Body RequestBody body and wrap String JSON object:

RequestBody body = RequestBody.create(MediaType.parse("application/json"), obj.toString());

answered Sep 14 '16 at 00:17

kkost

3,298
5
34
63

1

Solved the problem with this solution. Many thanks! – wdev733 Mar 17 '20 at 03:29

score 17 · Answer 2 · answered Sep 06 '19 at 09:41

17

You can specify a Converter when you create the Retrofit like this

Retrofit retrofit = new Retrofit.Builder()
        .addConverterFactory(GsonConverterFactory.create())
        .baseUrl(baseurl)
        .client(okHttpClient)
        .build();

answered Sep 06 '19 at 09:41

Emanuel

793
8
27

score 16 · Answer 3 · answered Apr 20 '20 at 08:30

16

there is chance of you kept same @SerializedName("") for multiple vairable/fields/tags

answered Apr 20 '20 at 08:30

Mohd Qasim

542
3
15

1

HA! This was my problem. Nice suggestion. – Taylor Kline Feb 22 '21 at 18:09
Wow, thank you! I wish error message was more clear on that – Kirill Starostin Jul 29 '21 at 17:10

score 3 · Answer 4 · answered Dec 01 '20 at 17:56

If this is due to @SerializedName make sure it is not dulplicated.

For e.g. This error will be thrown in below case: (Note: bookingId is passed twice)

@SerializedName(value="bookingId", alternate={"id", "bookingId"})

But, this is the correct:

@SerializedName(value="bookingId", alternate={"id", "someOtherId", "whateverId"})

Nikson Kanti Paul · Answer 5 · 2020-02-28T23:27:12.603

2

Body uses a single request object, declare your request object as following

class Inspection {
    String UUID;
    //..... add your fields 
    Project project;      
}

class Product
{
   int Id;
   //....... add your fields 
}

I assume your service IConstructSecureAPI endpoint is:

@GET(...)    // change based on your api GET/POST
Call<Response> addInspection(
    @Header("Authorization") String accesstoken, 
    @Body Inspection request
);

and you can declare your desire Response.

Check this answer, it uses HashMap instead of class.

edited Feb 28 '20 at 23:27

answered Mar 09 '16 at 04:22

Nikson Kanti Paul

3,288
1
33
50

Your answer is correct but I have forgot write ".addConverterFactory(GsonConverterFactory.create())" =) – Andrew Grow Feb 26 '20 at 11:20

score 1 · Answer 6 · answered Jan 04 '22 at 17:59

1

In my case I simply forgot to apply the kotlinx.serialization plugin for Gradle, so no code for the serializers was generated. Fix it via:

plugins {
    kotlin("plugin.serialization")
}

answered Jan 04 '22 at 17:59

sschuberth

26,156
6
93
139

score 0 · Answer 7 · edited Mar 11 '16 at 10:33

You can use an Interceptor to send Authorization Header in each request

class AuthorizationInterceptor implements Interceptor {

    @Override
    public Response intercept(Chain chain) throws IOException {
        Request originalRequest = chain.request();
        String authorizationToken = AuthenticationUtils.getToken();
        Request authorizedRequest = originalRequest.newBuilder()
            .header("Authorization", authorizationToken)
            .build();
        return chain.proceed(authorizedRequest);
    }
}

score 0 · Answer 8 · answered Nov 04 '21 at 12:30

I kept getting this error when I upgraded to Java 17, still working fine on Java 11.

Here's what worked for me

To go deeper into the Exception I put a debug point in the Utils.java found in retrofit stack trace.
Doing so led me to the narrower cause being: java.lang.reflect.InaccessibleObjectException: Unable to make field private final byte java.time.LocalTime.hour accessible: module java.base does not "opens java.time" to unnamed module @35e2d654
Googling down further from here led me to https://github.com/mockk/mockk/issues/681#issuecomment-959646598 which in a nutshell suggests to add --add-opens java.base/java.time=ALL-UNNAMED as a JVM argument.
Boom, It worked.

score 0 · Answer 9 · answered Nov 28 '21 at 14:23

I am using Moshi and Retrofit and my problem was I forgot to add @JsonSerializable annotation for the DTO class for @body. you should add this annotation like this:

@JsonSerializable
data class RegisterDTO(
    @field:Json(name = "device_id") val deviceId: String,
)

Retrofit: Unable to create @Body converter for class

9 Answers9

Here's what worked for me

Linked