Android Database: Couldn't read row 0, col 1 from CursorWindow

I have created a simple database table with username, title,and question. Here's my code for inserting and reading the data

public long insertData(String usernames,String title, String question) {
    SQLiteDatabase sqLiteDatabase =databaseHelper.getWritableDatabase();
    ContentValues contentValues = new ContentValues();
    contentValues.put(DatabaseHelper.USER, usernames);
    contentValues.put(DatabaseHelper.TITLE,title);
    contentValues.put(DatabaseHelper.QUESTION,question);
    long id =sqLiteDatabase.insert(DatabaseHelper.TABLE_NAME,null,contentValues);
    return id;
}
public String readData(){
    SQLiteDatabase sqLiteDatabase =databaseHelper.getWritableDatabase();
    String[] columns = {DatabaseHelper.USER};
    Cursor cursor = sqLiteDatabase.query(DatabaseHelper.TABLE_NAME, columns, null, null, null, null, null);
    StringBuffer buffer = new StringBuffer();
    while (cursor.moveToNext()) {
        int index0 = cursor.getColumnIndex(DatabaseHelper.UID);
        int index1 = cursor.getColumnIndex(DatabaseHelper.USER);
        int index2 = cursor.getColumnIndex(DatabaseHelper.TITLE);
        int index3 = cursor.getColumnIndex(DatabaseHelper.QUESTION);

        int cid = cursor.getInt(index0);
       String username = cursor.getString(index1);
        String title = cursor.getString(index2);
        String question = cursor.getString(index3);
        buffer.append(cid+" "+ username+" "+ title+ " "+ question);
    }

    return buffer.toString();
}

and here's my code for creating the database

static class DatabaseHelper extends SQLiteOpenHelper {
    private static final String DATABASE_NAME = "usserdatabase";
    private static final String TABLE_NAME = "usertable";
    private static final String UID = "_id";
    private static final int DATABASE_VERSION=1;
    private static final String USER = "UserName";
    private static final String TITLE="Title";
    private static final String QUESTION = "Question";
    private static final String UPGRADE_DATABASE = "DROP TABLE IF EXISTS "+ TABLE_NAME;
    private static final String CREATE_QUERY = "CREATE TABLE "+TABLE_NAME+" ("+UID +" INTEGER PRIMARY KEY AUTOINCREMENT, "+USER+" VARCHAR(255), "+TITLE+" VARCHAR(255), "+QUESTION+" VARCHAR(255));";


    public DatabaseHelper(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
        Log.d("Check","Constructer was called");
    }


    @Override
    public void onCreate(SQLiteDatabase db) {
        try{
            db.execSQL(CREATE_QUERY);
            Log.d("Check","Database Created Successfully!");
        }catch (SQLException e){
            Log.e("Check",e.getMessage());
        }

    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    try {
        db.execSQL(UPGRADE_DATABASE);
        onCreate(db);
        Log.d("Check","Databasae upgraded succesfully");
    } catch (SQLException e) {
        Log.e("Check",e.getMessage());
    }
    }
}

Whenever i call readData(), my app crashes. It saysjava.lang.IllegalStateException: Couldn't read row 0, col 1 from CursorWindow. Make sure the Cursor is initialized correctly before accessing data from it.