Spring JavaMailSender - best way to use session

Question

What's the best way to reuse sessions in Spring JavaMailSender?

In a scenario where a consumer reads messages from a queue and trigger emails based on the messages, the emails will be send one after the other. If a new session is created everytime, isn't that an overhead? If JavaMailSender is a singleton bean, does it use the same session always? What's the best solution here?

I saw samples of JNDI sessions being set in to JavaMailSender bean configuration. We don't have support for JNDI, so that's not an option.

Answer 1

If you use the standard JavaMailSender for the MailSendingMessageHandler , so you just reuse the Session !

// Check transport connection first...
if (transport == null || !transport.isConnected()) {
...
try {
    transport = connectTransport();
}

...

Transport transport = getTransport(getSession());
transport.connect(getHost(), getPort(), username, password);
return transport;

...

public synchronized Session getSession() {
    if (this.session == null) {
        this.session = Session.getInstance(this.javaMailProperties);
    }
    return this.session;
}

Not sure from where you heard that a new session is created for each message...