[milo-dev] issue - eclipse milo: subscription stops receiving updates ab

[Lenovo K3 Owner <lenovo.k3.1.owner@xxxxxxxxx>]

I have java application that makes the connection to zenon opc ua server using eclipse milo and subscribes for data changes for some set of nodes.

 - sdk-client used version is 0.2.5  

In general, all works nice.

But sometimes I observe error case when I stop receiving updates from the server at all (neither OK nor BAD nor UNCERTAIN).

I have no errors reported by milo (using UaSubscriptionManager.SubscriptionListener).

And client connection is alive (I can read any nodes involved in subscription using :

client.getAddressSpace().getVariableNode(nodeId).get().readValue().get();

From the zenon side I see changes of nodes using uaExpert, but as I said no updates on eclipse milo client side.

my questions are:

1. what can be a possible reason?
2. is there a way to check if the subscription is actually alive (i am not quite sure when i must receive   ?org.eclipse.milo.opcua.sdk.client.api.subscriptions.UaSubscriptionManager.SubscriptionListener#onKeepAlive)   ?
3. is there a way to force server to send current values of subscription ?
4. is there a way to handle (be informed at least) regular heartbeats between client and server ?

Thanks in advance