Spring Websocket (ActiveMQ): Stomp subscribe and get messages enqueued from a Topic - spring

Question

I am working with Spring WebSocket and Stomp.
Note: the broker is ActiveMQ
I have two #Schedule methods that sends messages to Queue and Topic respectively
For a subscription for a Queue, the code is as follows:
$('#ws_connect').click(function(){
console.log('Connect clicked');
var socket = new SockJS('/project-app/ws/notification');
stompClient = Stomp.over(socket);
stompClient.connect({}, function (frame) {
console.log('Connected: ' + frame);
$('#notification').append('<p>Connected</p>');
stompClient.subscribe('/queue/somedestination', function (notification) {
... append the content to the html page, it works
});
});
});
If there is no user the Queue is getting message by message. Once the user arrives and do the connection, automatically it gets all the messages enqueued and the Queue pass to be empty. If a new message arrives it appears automatically, it because the user remains connected yet. If the user disconnects and later do the connection, it can see again all the messages enqueued. Until here all is Ok
As follows for a subscription for a Topic
$('#ws_connect').click(function(){
console.log('Connect clicked');
var socket = new SockJS('/project-app/ws/notification');
stompClient = Stomp.over(socket);
stompClient.connect({}, function (frame) {
console.log('Connected: ' + frame);
$('#notification').append('<p>Connected</p>');
stompClient.subscribe('/topic/somedestination', function (notification) {
... append the content to the html page, it works
});
});
});
Practically the js code is the same than the Queue version. Just the destination is different.
Here the problem is that if exists messages enqueued in the Topic and if the user does the connection the messages do not appear automatically. Of course meanwhile the user remains connected he can see each new message, same case if multiple users are connected to the same Topic all can see the same new message.
But again for the first user to connect to the Topic destination. He is not able to get the messages enqueued from that Topic when he does the connection.
Is it the normal behaviour?
How can be retrieved the messages enqueued?
Perhaps a suggested approach to handle this scenario?
In some way the "worst" scenario would be create multiple Queues for each potential user. But just curious if through Topic is possible get this requeriment

Answer 1

The Topic destination does not store messages when there are no subscribers so the code is working as expected. The only time a Topic would retain messages for subscribers is if the subscriber had created a durable topic subscription and then gone offline at which point the broker would store any message sent to the Topic with the persistent flag enabled. The caveat here being that any message sent to that Topic before the subscription is made would be dropped.
See the documentation for more help.