I am unable to send email automatically from tab. However the same code works for mobile.. But not for tab

Question

I dont know y i am unable to send mail from tab. It gives exception saying cud not communicate, network unreachable. Gmailsender.java

public class GMailSender extends javax.mail.Authenticator {
private String mailhost = "smtp.gmail.com";
private String user;
private String password;
private Session session;
private Multipart _multipart = new MimeMultipart();
static {
    Security.addProvider(new JSSEProvider());
}
public GMailSender(String user, String password) {
    this.user = user;
    this.password = password;
    Properties props = new Properties();
    props.setProperty("mail.transport.protocol", "smtp");
    props.setProperty("mail.host", mailhost);
    props.put("mail.smtp.auth", "true");
    props.put("mail.smtp.port", "465");
    props.put("mail.smtp.socketFactory.port", "465");
    props.put("mail.smtp.socketFactory.class",
            "javax.net.ssl.SSLSocketFactory");
    props.put("mail.smtp.socketFactory.fallback", "false");
    props.setProperty("mail.smtp.quitwait", "false");
    props.setProperty("mail.smtp.ssl.enable", "true");

    session = Session.getDefaultInstance(props, this);

}
protected PasswordAuthentication getPasswordAuthentication() {

    return new PasswordAuthentication(user, password);

}
public synchronized void sendMail(String subject, String body,
                                  String sender, String recipients) throws Exception {
    try {
        MimeMessage message = new MimeMessage(session);
        DataHandler handler = new DataHandler(new ByteArrayDataSource(
                body.getBytes(), "text/plain"));
        message.setSender(new InternetAddress(sender));
        message.setSubject(subject);
        message.setDataHandler(handler);
        BodyPart messageBodyPart = new MimeBodyPart();
        messageBodyPart.setText(body);
        _multipart.addBodyPart(messageBodyPart);
        // Put parts in message
        message.setContent(_multipart);
        if (recipients.indexOf(',') > 0)
            message.setRecipients(Message.RecipientType.TO,
                    InternetAddress.parse(recipients));
        else
            message.setRecipient(Message.RecipientType.TO,
                    new InternetAddress(recipients));
        Transport.send(message);
    } catch (Exception e) {
        e.printStackTrace();
    }
}

 public class ByteArrayDataSource implements DataSource {
    private byte[] data;
    private String type;
    public ByteArrayDataSource(byte[] data, String type) {
        super();
        this.data = data;
        this.type = type;
    }

    public ByteArrayDataSource(byte[] data) {
        super();
        this.data = data;
    }

    public void setType(String type) {
        this.type = type;
    }

    public String getContentType() {

        if (type == null)
            return "application/octet-stream";
        else
            return type;
    }

    public InputStream getInputStream() throws IOException {
        return new ByteArrayInputStream(data);

    }
    public String getName() {
        return "ByteArrayDataSource";
    }

    public OutputStream getOutputStream() throws IOException {
        throw new IOException("Not Supported");
    }
}
}

I called this from activity as below.

GMailSender gMailSender=new GMailSender("user@abc.com","passwd");
gMailSender.sendMail(subject,message,"user@abc.com","to@abc.com");

Any suggestion wil be very helpful.