NullPointerException while accessing SQLite from non-activity class

Question

While accessing SQLite from non-activity class, getting NullPointerException

File -> SessionDB.java

public class SessionDB {

private SQLiteDatabase database;
private SQLiteHelper dbHelper;
private String[] allColumns = { SQLiteHelper.SESSION_ID,
  SQLiteHelper.SESSION_STRING };

public SessionDB(Context context) {
    dbHelper = new SQLiteHelper(context);
}

public void open() throws SQLException {
    database = dbHelper.getWritableDatabase();
}

public void createSession(String session_string) {
    ContentValues values = new ContentValues();
    values.put(SQLiteHelper.SESSION_STRING, session_string);
    database.insert(SQLiteHelper.SESSION_TABLE, null, values); // NullPointerException Here
}
}

File ->Live.java

public class Live {
    protected Context context;

    public Live(Context context) {
        this.context = context;
    }

    public accessOK {
        SessionDB ses = new SessionDB(context);
        ses.createSession("Sample"); // NullPointerException
    }

}

Then, what should be the best way to do this?

Answer 1

You don't seem to be calling SessionDB.open() anywhere. This means that your database field is never being initialized, so is null when you call SessionDB.createSession().