SMS relay --> MySQL database

The main purpose of my program is to extract GPS information from text messages sent to several GSM modems send from various GPS tracking devices. The main flow of my program loops in three steps:

• Receive SMS message (with the help of SMSlib)
• Extract data with regex
• Push data to MySQL database

I've only been exposed to Java for half a year and I would be honored to receive some feedback on my code - it is working at the moment. Should I split my code in seperate classes - nested class? Are there any smarter/more elegant ways of doing the things I do? Any general feedback on my code and my style?

(My massive abuse of print statements is only for debugging purposes doing development.)

Main "driver" class (some kind of GUI in the future):

public class GUI {
    public static void main(String[] args) {
        SMSRelay relay = new SMSRelay();
        try {
            System.out.println("Configuring gateway...");
            relay.addGateway("modem1", "COM4", "3716");
            System.out.println("Starting service...");
            relay.start();
            System.out.println("Listening... - Hit <enter> to stop service.");
            System.in.read();
        } catch (Exception e) {
            System.out.println("Something went wrong ...");
        } finally {
            try {
                relay.stop();
                System.out.println("SMSRelay stopped");
            } catch (Exception e) {
                System.out.println("Failed to stop the service...");
            }
        }
    }
}

SMSRelay class:

public class SMSRelay {
    private Service instance;

    public SMSRelay() {
        instance = Service.getInstance();
        instance.setInboundMessageNotification(new InboundHandling()); 
    }

    public void addGateway(String name, String port, String pin) throws GatewayException {
        SerialModemGateway g = new SerialModemGateway(name, port, 115200, "Huawei", "E220");
        g.setProtocol(Protocols.PDU);
        g.setInbound(true);
        g.setOutbound(true);
        g.setSimPin(pin);
        g.getATHandler().setStorageLocations("SMME"); //To prevent duplicate texts
        instance.addGateway(g);
    }

    public void removeGateway(String name) throws GatewayException {
        instance.removeGateway(instance.getGateway(name));
    }

    public void start() throws Exception  {
        instance.startService();
    }

    public void stop() throws Exception {
        instance.stopService();
    }

    public class InboundHandling implements IInboundMessageNotification {
        private Pattern p = Pattern.compile("lat: (?<lat>\\d+\\.\\d+) long: (?<lng>\\d+\\.\\d+).*imei:(?<imei>\\d+)");

        public void process(AGateway gateway, MessageTypes msgType, InboundMessage msg) {
            java.text.SimpleDateFormat formatter = new java.text.SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
            String date = formatter.format(msg.getDate());
            String originator = msg.getOriginator();
            String text = msg.getText();

            //Delete message from SIM
            try {
                instance.deleteMessage(msg);    
            } catch (Exception e) {
                System.out.println("Failed to delete message...");
            }

            //Look for GPS data         
            Matcher m = p.matcher(text);
            if (m.matches()) {
                System.out.println("Parsing valid info to database...");
                toDatabase(m.group("lat"), m.group("lng"), m.group("imei"), date, originator);
            } else {
                System.out.println("Invalid SMS");
                System.out.println(text);
            }
        }

        private void toDatabase(String lat, String lng, String imei, String date, String originator) {  
            Connection con = null;
            PreparedStatement pst = null;

            try {
                //Get MySQL info from properties file
                Properties props = new Properties();
                props.load(new FileInputStream("properties/database.properties"));
                String url = props.getProperty("db.url");
                String user = props.getProperty("db.user");
                String password = props.getProperty("db.passwd");

                System.out.println("Connecting to database...");

                //Connect to database   
                con = DriverManager.getConnection(url,user,password);

                System.out.println("Writing...");

                //Write data
                pst = con.prepareStatement("INSERT INTO positions VALUES (default, ?, ?, ?, ?, ?)");
                pst.setString(1, date);
                pst.setString(2, lat);
                pst.setString(3, lng);
                pst.setString(4, originator);
                pst.setString(5, imei);
                pst.executeUpdate();

                System.out.println("Data has been written!");

            } catch (IOException e) {
                System.out.println("Can't access database.properties!");
            } catch (SQLException e) {
                System.out.println("Something went wrong while interacting with database...");
                while (e != null) {
                      System.out.println ("SQLState: " + e.getSQLState () + "");
                      System.out.println ("Message: " + e.getMessage() + "");
                      System.out.println ("Vendor ErrorCode: " + e.getErrorCode() + "");
                      e = e.getNextException();
                      System.out.println("");
                }
            } finally {
                try {
                    if (pst != null) pst.close();
                    if (con != null) con.close();        
                } catch (SQLException e) {
                    System.out.println("Something went wrong closing the connections...");
                }  
            }   
        }
    }
}