Converting parse object to array of custom object in Java (Android Studio)

Question

I'm learning to program on Java and I've been really frustrated because I can't find a way to convert a parse.com object that I download to a costume class.

What I'm doing:

      public void downloadInformation() {
    usuario = ParseUser.getCurrentUser();

      ParseQuery<ParseObject> query = ParseQuery.getQuery("Glucosa");
      query.whereEqualTo("usuario", usuario);
      query.orderByDescending("createdAt");

      query.findInBackground(new FindCallback<ParseObject>() {
            @Override
          public void done(List<ParseObject> objects, ParseException e) {
              if (e == null && objects.size() > 0) {
                  Log.d("score", "Objects Retrived");
                  int i = 0;
                  for (ParseObject object : objects) {

                      dataArray = new MyData[objects.size()];

                    dataArray[i] = new MyData(object.getInt("glucosa"), object.getInt("insulina"), object.getDate("fecha"), object.getInt("Alimentos"), object.getString("Comentarios"));

                    i++;


                  }

                for (int j=0; j <= dataArray.length; j++){
                  Log.i("Working?", dataArray[j].comentarios);
                }




              } else {
                  Log.d("score", "error");

              }

          }


      });
}

The code of MyData is:

public class MyData {

    Integer gluc;
    Integer insulinaV;
    Date fec;
    Integer alimento;
    String comentarios;

    public MyData(Integer gluc, Integer insulinaV, Date fec, Integer alimento, String comentarios) {
        this.gluc = gluc;
        this.insulinaV = insulinaV;
        this.fec = fec;
        this.alimento = alimento;
        this.comentarios = comentarios;
    }

    public Integer getGluc() {
        return gluc;
    }

    public Integer getInsulinaV() {
        return insulinaV;
    }

    public Date getFec() {
        return fec;
    }

    public Integer getAlimento() {
        return alimento;
    }

    public String getComentarios() {
        return comentarios;
    }
}

But it doesn't matter what I try to recover, dataArray is alway empty. Even if I try to print dataArray.length it crashes.

What am I doing wrong?, What is the correct way to store an object like this? One almost of topic question, is there an easiest way to do this? in SWIFT for example I use a struct with objects.map, but I haven't find a method that can do this.

Thanks!!

Edit: There are 22 elements in objects, but the array dataArray is always null.

The error message I get is:

java.lang.NullPointerException: Attempt to read from field 'java.lang.String com.parse.starter.MyData.comentarios' on a null object reference

The null object reference comes even if I simply try to get the size of the dataArray.