Why is System.exit() required for use of AmqpTemplate?

[jccartwright]

Hello All,

I'm looking at a very simple example sending a message using AmqpTemplate#convertAndSend. I don't understand why the program won't terminate w/o an explicit System.exit(0).

Is it because it's waiting on an ACK?

Can someone please explain?

Thanks!

--john

@Grapes([
@Grab(group='org.springframework.amqp', module='spring-rabbit', version='1.1.3.RELEASE')
])

public class SendAmqp {
public static void main(String[] argv) throws Exception {
ConnectionFactory connectionFactory = new CachingConnectionFactory();
connectionFactory.host = "localhost"

AmqpAdmin admin = new RabbitAdmin(connectionFactory);
admin.declareQueue(new Queue("myqueue"));

AmqpTemplate template = new RabbitTemplate(connectionFactory);
template.convertAndSend("myqueue", "foo")

//without this, program won't exit
System.exit(0)
}
}

[Gary Russell]

Well, the CachingConnectionFactory, er, caches the connection; the connection has a non-daemon thread.

Change

ConnectionFactory connectionFactory ...

to

CachingConnectionFactory connectionFactory ...

and add

connectionFactory.destroy();

BTW, when posting, always surround code/config with [ code ] ... [ / code ] (no spaces inside brackets).

[jccartwright]

Thanks for the prompt response Gary. Given that the CachingConnectionFactory is the reason, I'm surprised that the following terminates w/o the System.exit nor the connectionFactory.destroy()

public class SendAmqp {
	public static void main(String[] argv) throws Exception {
		CachingConnectionFactory connectionFactory = new CachingConnectionFactory();
		connectionFactory.host = "localhost"
	}
}

--john

[Gary Russell]

Because in that case you never use the factory, so the connection is not opened/cached.

As soon as you declare the queue and/or send a message, the connection is opened and cached; the rabbit library maintains a thread for each connection to handle asynchronous incoming data.