Why JMS if we can use JAVA classes for the same

Question

if we can communicate using the java classes which are protable and platform independent why do we have to use JMS for that. what is so specific about it and what is the benefit that makes it outstanding

Answer 1

James/Steve,
I feel that some of your points are misleading. The original authors point was a comparison against JMS and other means of achieving similar functionality with Java. Regarding your combined points:
2) Scalability is something that can be achieved regardless of whether JMS is used. Clustering has nothing to do with JMS, each vendors clustering implementation is entirely proprietary.
4) Aside from the inclusion of JNDI the JMS specification offers nothing for management. You only need to look through this forum at the amount of times a question like �how do I make a topic programmatically?� has been asked. All good JMS vendors offer management API�s and tools but all are vendor specific implementations.
10) There is no JMS standard for load balancing. The generic round robin features of a JMS queue falls a long way short of true �load balancing�. Any vendor (ourselves included) that offers load balancing does so in an entirely proprietary manner.
11) Again�JMS provides no standards for clustering of running one or more server. This is entirely down to implementation and functionality is vendor specific.
12) Dead Message/Letter Queues are not defined in JMS
14) What does serialization have to do with the original point? How one chooses to serialize their content ( XML, Object Serialization, Externalizable etc..) is equally applicable to both bespoke Java coding and JMS implementations.
To birs1982:
JMS is merely a collection of interfaces that define how one might read and write to a topic or queue. Vendors (both open source and commercial) recognize that these interfaces alone are not enough to offer an entire middleware messaging solution and complete the offering with sophisticated management, resilience, clustering, security and other value added features. These value added features require considerable effort to get right as do things like scalability and performance.
Given JMS like messaging is almost commodity now (just look at the amount of JMS vendors that have leaped into the ESB space) and a common (perhaps essential) infrastructure component why produce it yourself? Surely your time is better spent serving your clients and business lines rather that writing what amounts to plumbing. All the hard work has been done and the price for this hard work (depending on your requirements) is anything from free to many thousands of pounds.
Regards,
Paul Brant
my-Channels - Technologies working together
http://www.my-channels.com/