Retrofit: Unable to create @Body converter for class

user_2876310 0
Viewed 34176

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

retrofit retrofit2 json java
9 Answers

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

user_82583050

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();
user_15061530

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"})
user_10542450

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.
user_80571270

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")
}
user_11274850

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,
)
user_106991190
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