Passing loc array with other params inside raw body in retrofit

Question

i am new to retrofit and getting problem in sending my data to server

i am trying to hit registration api from my mobile application with raw body which is as follows :-

     {
  "fullName": "test user",
  "gender": "male",
  "age": 25,
  "email": "[email protected]",
  "phoneNumber": 7696016749,
  "password": "Admin123#",
  "loc": [30.5234234, 75.4645646545]  ,
  "deviceId": "adssads90ads89afyh89sayfs89afs90afys890afsa",
  "deviceType": "ios"
}

if i hit this in post man it's working fine,but with code it's not here i am posting some of my code please review and let me know where i am doing wrong.

POJO of the response :-

    public class RequestModel {

    @SerializedName("fullName")
    @Expose
    private String fullName;
    @SerializedName("gender")
    @Expose
    private String gender;
    @SerializedName("age")
    @Expose
    private Integer age;
    @SerializedName("email")
    @Expose
    private String email;
    @SerializedName("phoneNumber")
    @Expose
    private Integer phoneNumber;
    @SerializedName("password")
    @Expose
    private String password;
        @SerializedName("loc")
    @Expose
    private List<Double> loc = null;
    @SerializedName("deviceId")
    @Expose
    private String deviceId;
    @SerializedName("deviceType")
    @Expose
    private String deviceType;

    public String getFullName() {
        return fullName;
    }

    public void setFullName(String fullName) {
        this.fullName = fullName;
    }

    public String getGender() {
        return gender;
    }

    public void setGender(String gender) {
        this.gender = gender;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public Integer getPhoneNumber() {
        return phoneNumber;
    }

    public void setPhoneNumber(Integer phoneNumber) {
        this.phoneNumber = phoneNumber;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public List<Double> getLoc() {
        return loc;
    }

    public void setLoc(List<Double> loc) {
        this.loc = loc;
    }

    public String getDeviceId() {
        return deviceId;
    }

    public void setDeviceId(String deviceId) {
        this.deviceId = deviceId;
    }

    public String getDeviceType() {
        return deviceType;
    }

    public void setDeviceType(String deviceType) {
        this.deviceType = deviceType;
    }
}

Service class :-

public interface ApiService {

    @POST("/api/registration")
    Call<ResponseModel> registerResponse(@Body RequestModel loginData);
}

My method of hitting api -

RequestModel contactsModel = new RequestModel();
        contactsModel.setFullName(username);
        contactsModel.setGender(gender);
        contactsModel.setEmail(email);
        contactsModel.setDeviceType("ios");
        contactsModel.setDeviceId("adssads90ads89afyh89sayfs89afs90afys890afsd");
        List<Double> list = new ArrayList<>();
        list.add(30.98877);
        list.add(72.857564);
        contactsModel.setLoc(list);
        apiService = RestClient.getClient().create(ApiService.class);
        Call<ResponseModel> getAllServerContacts = apiService.registerResponse(contactsModel);
        getAllServerContacts.enqueue(new Callback<ResponseModel>() {
            @Override
            public void onResponse(Call<ResponseModel> responseModel, Response<ResponseModel> response) {

                Alerts.dismissLoadingDialog();
                try {
                    if (response.isSuccessful()) {


                        ResponseModel contactsVerified = response.body();
                        SignupModel signupModel = contactsVerified.getSignupModel();
                        String name = signupModel.getFullName();

                    } else {
                        Log.e("nOt", "Successful");
                    }


                } catch (Exception e) {
                    e.printStackTrace();
                }

            }

            @Override
            public void onFailure(Call<ResponseModel> call, Throwable t) {
                Alerts.dismissLoadingDialog();
                Log.e("nOt", "Successful");
            }


        });

Location params are not going correct they ate receiving as ['30.5234234', '75.4645646545'] instead of [30.5234234, 75.4645646545].

Please let me know how to do this in case of retrofit.

Thanks