我正在后台(在命令提示符下)运行电子邮件服务,这是为了继续运行并在队列表中提取记录以进行处理.

这是我的Email.java：

public class Email {
    MysqLConnect con=new MysqLConnect();
    public PreparedStatement preparedStatement = null;
    public Connection con1 = con.connect();
    public Email() throws Exception {
    }
    //pick up queue and send email
    public void email() throws Exception {
        try{
            while(true) {
                String sql = "SELECT id,subject,recipient,content FROM emailqueue WHERE status='Pending' ";
                PreparedStatement statement = con1.prepareStatement(sql);
                ResultSet rs = statement.executeQuery();
                while (rs.next()) {
                    String subject = rs.getString("subject");
                    String recipient = rs.getString("recipient");
                    String content = rs.getString("content");
                    String id = rs.getString("id");
                    sendEmail(recipient,content,id);
                }
            }
        }catch(Exception e){
            e.printStackTrace();
        }
        con1.close();
        Thread.sleep(2000);
    }
//Schedule a service for picking email
    public void schedule(){
        Thread service;
        service = new Thread(new Runnable() {
            public void run() {
                try {
                    System.out.println("Email service is ready");
                    email();
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
        service.start();
    }
    public void sendEmail(String recipient,String subject,String content,String id) {
        try {
            //final String fromEmail = "lordjesus0371@gmail.com"; //requires valid gmail id
            // final String password = "htasia123"; // correct password for gmail id
          //  InitialContext ctx = new InitialContext();
            String host = get_attributevalue("MAIL_SERVER");
            String port = get_attributevalue("MAIL_PORT");
            final String senderaddress = get_attributevalue("SENDER_ADDRESS");
            final String password = get_attributevalue("MAIL_PASSWORD");
            System.out.println("Please Wait,sending email...");
            /*Setup mail server */
            Properties props = new Properties();
            props.put("mail.smtp.host",host); //SMTP Host
            props.put("mail.smtp.port",port); //TLS Port
            props.put("mail.smtp.auth","true"); //enable authentication
            props.put("mail.smtp.starttls.enable","true"); //enable STARTTLS
            //create Authenticator object to pass in Session.getInstance argument
            Authenticator auth = new Authenticator() {
                //override the getPasswordAuthentication method
                protected PasswordAuthentication getPasswordAuthentication() {
                    return new PasswordAuthentication(senderaddress,password);
                }
            };
            Session session = Session.getInstance(props,auth);
            session.setDebug(true);
            // Define message
            MimeMessage message = new MimeMessage(session);
            // Set From: header field of the header.
            message.setFrom(new InternetAddress(senderaddress));
            message.addRecipients(Message.RecipientType.TO,InternetAddress.parse(recipient));
            // Set Subject: header field
            message.setSubject(subject);
            // Now set the actual message
            message.setText(content);
            Transport.send(message);
            delivered(id);
            System.out.print("Email sent");
        } catch (Exception e) {
            System.out.println(e.getMessage());
            try{
                error(id);
            } catch (sqlException e1) {
                e1.printStackTrace();
            }
        }
    }

在我的Main方法中：

public static void main(String[] args) throws Exception {
        Email runEmailService=new Email();
        runEmailService.schedule();
    }

它能够提取记录并处理电子邮件,但是一段时间后会抛出：

Exception in thread "Thread-1" java.lang.OutOfMemoryError: Java heap space
Exception: java.lang.OutOfMemoryError thrown from the UncaughtExceptionHandler in thread "Thread-1"

并且程序停止运行.

有没有一种方法可以防止这种情况的发生,使我的程序继续运行？