IllegalArgumentException: Could not locate call adapter for rx.Observable RxJava, Retrofit2
<p>I am getting the above error while calling the rest api. I am using both retrofit2 and RxJava.</p>

<h2>ServiceFactory.java</h2>

<pre><code>public class ServiceFactory {
public static &lt;T&gt; T createRetrofitService(final Class&lt;T&gt; clazz, final String endpoint){

    Retrofit retrofit = new Retrofit.Builder()
            .baseUrl(endpoint)
            //.addConverterFactory(GsonConverterFactory.create())

            .build();

    T service = retrofit.create(clazz);
    return service;
}
</code></pre>

<p>}</p>

<h2>MovieService.java</h2>

<pre><code>public interface MovieService{
//public final String API_KEY = "&lt;apikey&gt;";
public final String SERVICE_END = "https://api.mymovies.org/3/";
@GET("movie/{movieId}??api_key=xyz")
Observable&lt;Response&lt;Movies&gt;&gt; getMovies(@Field("movieId") int movieId);
</code></pre>

<p>}</p>

<h1>Inside MainActivity</h1>

<pre><code>      MovieService   tmdbService = ServiceFactory.createRetrofitService(MovieService.class, MovieService.SERVICE_END);
    Observable&lt;Response&lt;Movies&gt;&gt; responseObservable = tmdbService.getMovies(400);
    responseObservable .subscribeOn(Schedulers.newThread())
            .observeOn(AndroidSchedulers.mainThread())
            .subscribe(new Subscriber&lt;Response&lt;Movies&gt;&gt;() {
                @Override
                public void onCompleted() {

                }

                @Override
                public void onError(Throwable e) {

                }

                @Override
                public void onNext(Response&lt;Movies&gt; moviesResponse) {

                }
            });
</code></pre>