Implementing Room SQLIte in new Thread

What is the best practise for getting data from Room SQLite from a new thread to main UI thread in android?

A little reminder : This AsyncTask solution is just for quick implementation for a few queries. If you have lots of different queries, don't try to create a bunch of AsyncTask subclasses to handle. Better look at the LiveData way or manage a thread yourself.

Assuming you are querying for list of all users :

@Dao
public interface UserDao {
    @Query("Select * FROM User")
    List<User> findAll();
}

Sample async task

private static class UserTask extends AsyncTask<Void, Void, List<User>> {
    UserDao dao;

    public UserTask(UserDao dao) {
        this.dao = dao;
    }

    @Override
    protected List<User> doInBackground(Void... voids) {
        // this function runs in a background thread managed by system
        return dao.findAll();
    }

    @Override
    protected void onPostExecute(List<User> users) {
        // This runs in UI thread after doInBackground return. Run your ui callback here
        super.onPostExecute(users);
    }
}