I have been looking on JMS these days and will work on JMS in near
future. Below is what I learned from the tutorials -

JMS provider is a server/provider that manages the queue/topic
depending upon the messaging models used. The sender sends the messages
to the queue that exist on provider and receiver fetches the messages
from the provider.

2 types of messaging domains are there -

Point to Point
-    As the name suggest, this is one to one messaging. For every message
there will be a consumer/receiver.
-    A queue is assigned for a receiver and the receiver receives the
messages from that queue only.
-    One queue can be assigned for multiple receivers.
-    The receiver can retrieve the messages from the queue independent of
the time (i.e. before the message is timed out). It can be possible
that the sender put the message on the queue when the receiver was not
running, but still receiver can receive the message when it wakes up.
-    On successful processing of messages, receiver gives acknowledgement.

Publish/Subscribe
-    This is one to many messaging. Each message may have multiple
consumers.
-    Publishers & Subscribers have time dependency. The subscriber must be
active in order for it to consume message.

Please put on your comments on this or you can extend it further if you
want to add some to this. Tell me whether my understanding is correct
or not. Ideas of application that utilizes various features of JMS will
be a great help.