Justification of using Spring

I'm trying to using Spring in my design for a web app,
but the manager wants me to justify it. I need Spring
promoter's help.

If you need help justifying it, why would you want to use it? If you can't come up with any good reasons on your own, perhaps your manager is right?

Tell your manager about IOC, AOP which are great features of Spring and not available in new J2EE Technologies...

Deepak......

"Deepak", please check your private messages.

Originally posted by Deepak:
Tell your manager about IOC, AOP which are great features of Spring

But what do these patterns bring to the application? Why is it desirable? And is Spring worth it?

and not available in new J2EE Technologies...

Nonsense. Spring is written in Java like everything else. These patterns, if desired, are available to everyone.

Tell your manager about IOC, AOP which are great features of Spring and not available in new J2EE Technologies

Java EE 5 is built on the idea of IoC and EJB 3 is shipped with AOP (maybe not as rich as Spring AOP, but it serves you well).

If you cannot justify it yourself, it's probably not worth it. I agree with the others that you should not go for Spring just for the hell of it. But if you want to check what it can help you to achieve, check out this overview. This recent article may also interest you.
[ November 12, 2007: Message edited by: Christophe Verre ]

Another issue about Spring is the performance.

The quickest way to create an instance of a class is to use "new" operator directly. You can apply some GOF patterns (Factory, Builder, ...) to
organize code better.

The slowest way is to use Java reflection, which Spring uses.

hi S. Palanigounder,

can you tell us where Spring uses reflection, and at what cost compared to the faster methods you mention?

Herman

When you define a class in applicationcontext.xml, something like:

...
<bean id="myDAO" class="com.work.MyDAOImpl" />
...

How does Java create an instance of com.work.MyDAOImpl using the data in
the xml file?

hi S. Palanigounder,

thanks for your reply.

But you did not answer my question about the performance cost of this, especially since Spring usually only has to create 1 instance of this class.
Can you post some numbers?

Herman
[ November 17, 2007: Message edited by: Herman Scheltinga ]

Yes, Spring uses reflection but not reflection facility of the JDK, AFAIK, it uses the open source counter part (I'm not sure which open source project), but it is performant.