Problem with sqlite and boot receiver

I have an application where the purpose is to put the name of a stop and after reboot to the android device get the name of that stop in reboot receiver

My boot receiver is working because I already tested it only gives error when I try to access data from my sqlite database where the error is NullPointerException;

Code where I create my sqlite database BDcore.java:

public class BDCore extends SQLiteOpenHelper {
 private static final String NOME_BD = "teste";
  private static final int VERSAO_BD = 6;

    public BDCore(Context ctx){
        super(ctx,NOME_BD , null , VERSAO_BD);

    }


        @Override
        public void onCreate(SQLiteDatabase db) {
            db.execSQL("create table favoritos(_id integer primary key autoincrement , favid intenger not null  , linha text not null, paragem text not null, horas text not null);");
            db.execSQL("create table utilizador(_id2 integer primary key autoincrement, utilizadorId integer not null);");
            db.execSQL("create table ultutilizador(_id3 integer primary key  autoincrement , ultid intenger not null);");
        }

        @Override
        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    db.execSQL("drop table favoritos");
    db.execSQL("drop table utilizador");
    db.execSQL("drop table ultutilizador");
            onCreate(db);
        }
    }

I put the data in my sqlite database through my user login activity:

 SQLiteDatabase db;
 BDCore auxBd = new BDCore (this);
    db = auxBd.getWritableDatabase();

 ContentValues valores = new ContentValues();
                valores.put("favid", 3);
                valores.put("linha", "teste");
                valores.put("paragem", "PARAGEMTESTE");
                 valores.put("horas", "teste");
                db.insert("favoritos", null, valores);

My boot receiver:

public class BootReceiver extends BroadcastReceiver {
    SQLiteDatabase db;

    String paragem;

    @Override
    public void onReceive(Context context, Intent intent) {

            String[] colunas = new String[]{"_id", "favid", "linha", "paragem" , "horas" };
            Cursor cursor2 = db.query("favoritos", colunas, null, null, null, null, null);
        HorariosActivity.context = context;
            if (cursor2.getCount() > 0) {
                cursor2.moveToFirst();
                do {

                    paragem = cursor2.getString(3);

                }
                while ( cursor2.moveToNext());

            }
        }

    }