Sending 120 mails by Javamail using Gmail account, but got exception after 80/90 mails

问题

Got the below exception while send mails in a loop of 120. First 80/85 mails are success but the remaining got exceptions.

javax.mail.MessagingException: Can't send command to SMTP host; nested exception is: java.net.SocketException: Connection closed by remote host at com.sun.mail.smtp.SMTPTransport.sendCommand(SMTPTransport.java:1564) at com.sun.mail.smtp.SMTPTransport.sendCommand(SMTPTransport.java:1551) at com.sun.mail.smtp.SMTPTransport.issueSendCommand(SMTPTransport.java:1489) at com.sun.mail.smtp.SMTPTransport.mailFrom(SMTPTransport.java:1054) at com.sun.mail.smtp.SMTPTransport.sendMessage(SMTPTransport.java:634)

Below is my code for sending mails. From, To, Subject, Body etc. are same for all 120 mails.

    try {
        Transport tr = session.getTransport("smtp");
        tr.connect(this.SMTPServer, this.UserName, this.Password);
        System.out.println("Successfully connected to the mail server.");
        tr.sendMessage(message, message.getAllRecipients());
    } catch (Exception ex) {
        ex.printStackTrace();
    }

来源：https://stackoverflow.com/questions/10135927/sending-120-mails-by-javamail-using-gmail-account-but-got-exception-after-80-90