Implementing DAO on a project where concrete class requires database connection

I'm trying to implement DAO pattern on my code,however I need mysql and sqlite connections in my concrete class since I do logic operations that require database entries. After creating this concrete class, I used it again to call these methods and use them, however it doesn't make any sense I guess since I created an interface for this, and should use it somehow.Should I also pass connections through my interface method-contracts?Please note that this works but I feel like I have done something redundant, so I'm asking for help.

I have a POJO class that I'm not going to post here,contains too much stuff and it's just a pojo class and has nothing to do with my question.

My DAO interface:

public interface AlarmDAO {

public List<Alarm> getAlarmList(String timestamp) throws SQLException, ParseException;
public void insertAlarm(byte[] backlog_id, Date timestamp) throws SQLException;}

And my concrete class:

public class AlarmConcrete implements AlarmDAO {
private SQLiteJDBC sqLiteJDBC;
private Utility utility;
private MysqlConnection mysqlConnection;
private Connection connection;
Statement stmt;
SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

public AlarmConcrete(MysqlConnection mysqlConnection,SQLiteJDBC sqLiteJDBC){
    this.sqLiteJDBC = sqLiteJDBC;
    this.mysqlConnection = mysqlConnection;
}

/**
 * @param timestamp
 * @return
 * @throws SQLException
 * @throws ParseException
 */
public List<Alarm> getAlarmList(String timestamp) throws SQLException, ParseException {
    List<Alarm> alarmList = new ArrayList<Alarm>();
    ResultSet rs = null;
    try {
        connection = mysqlConnection.getConnection();
        stmt = connection.createStatement();
        String modifiedStamp = "?"+timestamp+"?";
        String tokenize = modifiedStamp.replace("?","'");
        String query = "select * FROM alarm WHERE `timestamp` >= " + tokenize+ " ORDER BY `timestamp` ASC";
        rs = stmt.executeQuery(query);
        while (rs.next()) {
            Alarm alarmObject = new Alarm();
            alarmObject.setBacklogId(rs.getBytes("backlog_id"));
            Date date  = format.parse(rs.getString("timestamp"));
            alarmObject.setTimestamp(date);
            alarmObject.setEventId(rs.getBytes("event_id"));
            alarmList.add(alarmObject);
        }
    } catch (SQLException e) {
        e.printStackTrace();
    }
    return alarmList;
}

/**
 * @param backlog_id
 * @param timestamp
 * @throws SQLException
 */
public void insertAlarm(byte[] backlog_id, Date timestamp) throws SQLException {
    try{
        Statement statement=null;
        Connection conn = sqLiteJDBC.getLiteConnection();
        String modTime = "'"+format.format(timestamp)+"'";
        System.out.println("Database opened");
        System.out.println("VALUES ("+backlog_id+","+timestamp+")");
        statement =conn.createStatement();
        String sql = "INSERT INTO `alarm_entries` (`backlog_id`,`timestamp`)" + "VALUES (X'"+Utility.bytesToHex(backlog_id)+"'," +
                ""+modTime+")";
        statement.executeUpdate(sql);

        statement.close();
    }catch (Exception e){
        System.out.println("Couldn't insert latest alarm");
    }

    System.out.println("Records created");
}

}

I used it like this:

public ScheduledTask(MysqlConnection mysqlConnection,SQLiteJDBC conn) throws SQLException, ParseException, IOException {
    this.mysqlConnection = mysqlConnection;
    this.lastAlarm = new Alarm();
    this.dbUtil = new DBUtil(mysqlConnection);
    this.conn = conn;
    this.commandLineArgs = new CommandLineArgs();
    this.alarmEntryList = new AlarmConcrete(mysqlConnection,conn);
}...{....alarmEntryList.insertAlarm(lastAlarm.getBacklogId(), lastAlarm.getTimestamp());}

In last piece of code I initialized my concrete class in constructor of another class and used it in one of its methods, but again, why did I use interface in the first place?Many thanks