Retrofit

implementation 'com.google.code.gson:gson:2.8.2' implementation 'com.squareup.retrofit2:retrofit:2.4.0' implementation 'com.squareup.retrofit2:converter-gson:2.4.0' implementation 'com.squareup.okhttp3:logging-interceptor:3.9.1'

public class APIClient {

private static Retrofit retrofit = null;

public static APIService getApiClient(){

    if(retrofit == null){

        HttpLoggingInterceptor httpLoggingInterceptor = new HttpLoggingInterceptor();
        httpLoggingInterceptor.setLevel(HttpLoggingInterceptor.Level.BODY);
        OkHttpClient okHttpClient = new OkHttpClient.Builder()
                .addInterceptor(httpLoggingInterceptor)
                .connectTimeout(15, TimeUnit.SECONDS)
                .readTimeout(15, TimeUnit.SECONDS)
                .writeTimeout(15, TimeUnit.SECONDS).build();

        retrofit = new Retrofit.Builder()
                .baseUrl(ApiConst.BASE_URL)
                .client(okHttpClient)
                .addConverterFactory(GsonConverterFactory.create())
                .build();
    }
    return retrofit.create(APIService.class);
}

public APIService getInstance(){
    return retrofit.create(APIService.class);
}

}

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APIClient.getApiClient().login(loginReq)