Have a look @ the paper named:"J2EE and .NET: A Comparison" by this
site: http://isavix.com ! it may give u some idea.
I'm not telling this 'cause here is a Java EE group but Java
Technology has gone a long way through these enterprise needs.
putting new J2EE 5.0 spec upgrades away you still find many
frameworks and tools to overcome your enterprise problem.
Java has its own Persistance models which you won't find on
Microsoft Technologies. J2EE applications are SURE more scalable
than the other partner. Security issues are more answered at Java
side ( you can rely more on Linux than Windows ), you have tons of
libraries and tools to use ( mostly opensource so reducing your
costs ) and there's a good transaction support. Java's performance
in some cases realy is the matter when .Net has no ( as i know )
known performance problems and Microsoft's .Net has more support in
some cases to Java's OpenSource frameworks...

I'd choose Java if charasteristics
like "persistance", "transactional
processes", "scalablity", "reliability" and "security" realy was the
key!

I accept what friends say but I just wanna add 2 points:

1. We should not thinks that only Java EE or .NET can build large  scale
solutions. (Can .NET do it?). Lets have some experince and at least try
some relatively less famous solutions such as Ruby, Jini, Zope, CCM etc.

2. I don't think Java is cost/speed optimal for GUI esp. web! If i wanna
chose for web tier, I would like to go for sth. which needs less cosding
such as Velocity(wrapped Java) or ASP(i mean this)

1. We should not thinks that only Java EE or .NET can build large  scale
solutions. (Can .NET do it?). Lets have some experince and at least try
some relatively less famous solutions such as Ruby, Jini, Zope, CCM etc.


[Reply] Agree. Java and .Net are both powerful, as is Ruby or php or whatever. It really is a question of the quality of the people involved in a project. Hire good java programmers and your project has a much higher chance of success, hire good .Net programmers for the same project and the project may succeed equally. Konnandasho bayad dashteh bashi J I think this article reflects my points perfectly: www.joelonsoftware.com/articles/HighNotes.html


2. I don't think Java is cost/speed optimal for GUI esp. web! If i wanna
chose for web tier, I would like to go for sth. which needs less cosding
such as Velocity(wrapped Java) or ASP(i mean this)


[Reply] Agree to some extent. I’ve heard google uses webwork+velocity for its web stuff (or some of it?). Be clever about the technology  you choose, don’t get fooled by “standards”. Choose a standard only if it’s a good standard.

If you looked at the recent messages, you would find
a message titled "101 Reasons Why Java is Better than .NET".
Try the link below for more information:

www.manageability.org/.../WhyJavaIsBetterThanDotN
et

and know that the guys here are j2ee  experts not .NET experts,
so the only thing they will tell you is CHOOSE JAVA as I do.

I had two year experience on .NET and never gonna
try it anymore.
First because of not enough support for changes between .NET 2.0 and
1.1 both in UI and ADO .NET.
Second because you can't find anything comparable EJBs or POJOs
in Hibernate.
Third there are lots of unbelievable great frameworks like JAIN in
java.

4th. You can trust your own library in Java, write it once and use
it thousands times
but you always need some VS.NET wizards to change your codes to
campatible with new version of .NET, if there is no wizard your
poor developers should do it manually.

Let me know if you have any question about Java and .NET., I'll
be happy to share my experience/

you can use this paper to find your answer:
The Comparison of J2EE and .NET for e-Business

www.calstatela.edu/.../...techreport-102912003.pdf