Can Async Task write in internal storage android? - file

Question

Hi i need to download a file from url and save in internal storage,so the download process run in async task.
First, I have tried to write a string in a file with async task but give me error: Failed to create oat file.
The same code work without task, so my question is i must download the file in external storage and after move in internal?
private void writeInFile() {
FileOutputStream output = null;
String text = "TEXT";
try {
output = openFileOutput("nameFile.abc",Context.MODE_PRIVATE);
} catch (FileNotFoundException e) {
e.printStackTrace();
}
try {
output.write(text.getBytes());
output.flush();
output.close();
} catch (IOException e) {
e.printStackTrace();
}
}
But if i call this function in doInBackground of class that extend AsyncTask i receive the error.
LicenzaTask mt = new LicenzaTask(this);
mt.execute();
public class LicenzaTask extends AsyncTask<Void, Void, Void> {
private Context mContext;
public LicenzaTask(MainActivity mainActivity) {
mContext = mainActivity;
}
#Override
protected Void doInBackground(Void... voids) {
modifyFile();
return null;
}
private void modifyFile() {
File file = new File(mContext.getFilesDir() + "nome.abc");
String text = "text";
BufferedWriter output = null;
try {
output = new BufferedWriter(new FileWriter(file));
output.write(text);
} catch (IOException e) {
e.printStackTrace();
} finally {
if (output != null) {
try {
output.close();
} catch (IOException e) {
}
}
}
}