A Description of Java Messaging Service

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  • Topic: JavaServer Pages, Web server, Java
  • Pages : 8 (2165 words )
  • Download(s) : 59
  • Published : March 20, 2013
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Q:| What is JMS?|
A:| JMS is an acronym used for Java Messaging Service. It is Java's answer to creating software using asynchronous messaging. It is one of the official specifications of the J2EE technologies and is a key technology.|  | [ Received from Sandesh Sadhale] | TOP|

Q:| How JMS is different from RPC?|
A:| In RPC the method invoker waits for the method to finish execution and return the control back to the invoker. Thus it is completely synchronous in nature. While in JMS the message sender just sends the message to the destination and continues it's own processing. The sender does not wait for the receiver to respond. This is asynchronous behavior.|  | [ Received from Sandesh Sadhale] | TOP|

Q:| What are the advantages of JMS?|
A:| JMS is asynchronous in nature. Thus not all the pieces need to be up all the time for the application to function as a whole. Even if the receiver is down the MOM will store the messages on it's behalf and will send them once it comes back up. Thus at least a part of application can still function as there is no blocking.   |  | [ Received from Sandesh Sadhale] | TOP|

Q:| Are you aware of any major JMS products available in the market? | A:| IBM's MQ Series is one of the most popular product used as Message Oriented Middleware. Some of the other products are SonicMQ, iBus etc.All the J2EE compliant application servers come built with thier own implementation of JMS. |  | [ Received from Sandesh Sadhale] | TOP|

Q:| What are the different types of messages available in the JMS API? | A:| Message, TextMessage, BytesMessage, StreamMessage, ObjectMessage, MapMessage are the different messages available in the JMS API. |  | TOP |  |

Q:| What are the different messaging paradigms JMS supports?| A:| Publish and Subscribe i.e. pub/suc and Point to Point i.e. p2p.|  | [ Received from Sandesh Sadhale] | TOP|

Q:| What is the difference between topic and queue?|
A:| A topic is typically used for one to many messaging i.e. it supports publish subscribe model of messaging. While queue is used for one-to-one messaging i.e. it supports Point to Point Messaging.|  | [ Received from Sandesh Sadhale] | TOP|

Q:| What is the role of JMS in enterprise solution development?| A:| JMS is typically used in the following scenarios
1. Enterprise Application Integration: - Where a legacy application is integrated with a new application via messaging. 2. B2B or Business to Business: - Businesses can interact with each other via messaging because JMS allows organizations to cooperate without tightly coupling their business systems. 3. Geographically dispersed units: - JMS can ensure safe exchange of data amongst the geographically dispersed units of an organization. 4. One to many applications: - The applications that need to push data in packet to huge number of clients in a one-to-many fashion are good candidates for the use JMS. Typical such applications are Auction Sites, Stock Quote Services etc.|  | JSP| |

Q:| What is a output comment? |
A:| A comment that is sent to the client in the viewable page source.The JSP engine handles an output comment as uninterpreted HTML text, returning the comment in the HTML output sent to the client. You can see the comment by viewing the page source from your Web browser. JSP Syntax <!-- comment [ <%= expression %> ] -->

Example 1
<!-- This is a commnet sent to client on
<%= (new java.util.Date()).toLocaleString() %>

Displays in the page source:
<!-- This is a commnet sent to client on January 24, 2004 -->|  | TOP |

Q:| What is a Hidden Comment?|
A:| A comments that documents the JSP page but is not sent to the client. The JSP engine ignores a hidden comment, and does not process any code within hidden comment tags. A hidden comment is not sent to the client, either in the displayed JSP page or the HTML page...
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