Set - 3

Question 21 :

What are the core JMS-related objects required for each JMS-enabled application?

Answer :

Each JMS-enabled client must establish the following:
* A connection object provided by the JMS server (the message broker)
* Within a connection, one or more sessions, which provide a context for message sending and receiving
* Within a session, either a queue or topic object representing the destination (the message staging area) within the message broker
* Within a session, the appropriate sender or publisher or receiver or subscriber object (depending on whether the client is a message producer or consumer and uses a point-to-point or publish/subscribe strategy, respectively). Within a session, a message object (to send or to receive)


Question 22 :

How does the Application server handle the JMS Connection?

Answer :

1. App server creates the server session and stores them in a pool.
2. Connection consumer uses the server session to put messages in the session of the JMS.
3. Server session is the one that spawns the JMS session.
4. Applications written by Application programmers creates the message listener.


Question 23 :

What is Stream Message ?

Answer :

Stream messages are a group of java primitives. It contains some convenient methods for reading the data. However Stream Message prevents reading a long value as short. This is so because the Stream Message also writes the type information along with the value of the primitive type and enforces a set of strict conversion rules which actually prevents reading of one primitive type as another.