Which two options regarding the expiry of these messages are true?

You have a durable subscriber, and the subscriber is down or not reachable when the message is
produced. Which two options regarding the expiry of these messages are true?

A.
after the subscriber is unavailable for 10 minutes

B.
when the subscriber is available

C.
after the subscriber is unavailable for after an hour

D.
are available until the specified time elapses

E.
are expired instantly

Explanation:
By default, JMS messages never expire. When applications send messages to

queues or topics with durable subscribers, WebLogic must retain the message until it is
consumed. This is fine in most point-to-point messaging applications because consumers are
constantly consuming messages. Any message sent to a queue will typically be consumed in a
relatively short period of time. If the consumers get disconnected, they will usually reconnect as
soon as possible and start processing any messages that might have built up in the queue.
D: For durable subscribers to a topic, this is not necessarily true. The messaging system is forced
to retain any message that has not been consumed by a durable subscriber, regardless of whether
that durable subscriber will ever return. In this case, WebLogic is at the mercy of the durable
subscriber to unsubscribe when it no longer wishes to receive the messages. If the durable
subscriber logic is flawed in such a way that the subscribers do not unsubscribe properly, the
messaging system will start to fill up with messages that may never be delivered. This calls for real
caution in using durable subscribers. Fortunately, there is another way to help deal with this
problem. Message expiration can be set at the connection factory level. Using a connection
factory’s default time-to-live attribute, we can specify the number of milliseconds that WebLogic
should retain an undelivered message after it is sent.