Java - From Array Observable into a Array mapped from multiple Single operations

ArrayToSingleResult.java

import io.vertx.core.json.JsonArray;
import rx.Observable;
import rx.Single;

/**
 * @author abner2
 */
public class RxPlayground {

  public static void main(String[] args) {

    JsonArray jsonArray = new JsonArray().add(1).add(2).add(3);
    
    // toList => See http://tomstechnicalblog.blogspot.com.br/2015/11/rxjava-operators-tolist.html
    Object b = Observable
      .from(jsonArray.getList().toArray())
      .switchMap(x ->
        doSome((Integer) x).toObservable()
      )
      .toList()
      .toSingle()
      ;

    ((Single) b).subscribe(System.out::println);
    System.out.println(b);

    // Here, using Buffer operator
    Object c = Observable
      .from(jsonArray.getList().toArray())
      .switchMap(x ->
        doSome((Integer) x).toObservable()
      )
      .buffer(jsonArray.size())
      .toSingle()
      ;

    ((Single) c).subscribe(System.out::println);
    System.out.println(c);

  }

  public static Single<String> doSome(Integer ind) {
    return Single.just(new Integer(ind + 1).toString());
  }

}