Thanks for replying Pradip
In durable subscription messages are persisted. So the above case does not arise
If I am a topic publisher using the TopicPublisher.publish() method, I can specify the Delivery Mode argument to the publish() method as javax.jms.DeliveryMode.NON_PERSISTENT. Hence I am publishing a non-persistent message. But the topic subscriber can have a durable subscription to the topic. This is what I meant by the case of non-persistent messages and durable subscriptions. What will happen in this case?