When you are developing web applications you usually have to make  a choice between Java EE and .NET.  Here is some points you should take note of before you take the plunge.

.NET  relies on stored procedures, whereby in Java  preference is given to keep everything in domain objects outside the DB. On .Net side you can use NAnt or a proprietary MS tool.

In .NET you get everything from one vendor. Whereas in Java EE you get several IDE and implementations from SUN as well as other third party vendors.

You can get help from very helpful online Java community whereas you have to depend on MSDN for help in .NET .

You don’t have to search for a given solution in .NET. The choice is clear. It can save you a considerable amount of time. Whereas in Java you have to search for the right tool from the many tools that is available.

.NET tools description and  evaluation is given at MSDN whereas for Java you have to evaluate them yourself if you can’t trust reviews of strangers on the internet.

The UI best practices are more consistent in .NET than in Java. The language integration in .NET is seamless. You can  call methods from C# to VB.NET with ease. In Java it is difficult to call Scala functions from Groovy.

As for IDE you have several commercial and free IDE’s available for java but in the case of .NET. . . . .

Java integration is excellent. You get connectors for SAP, AS400, etc. for free. ESBs, LDAP servers are also free.

Java language very stable. There are no big changes. Java EE 5 and 6 platform is backward compatible.

You can choose whatever OS you want to for development and production in Java EE whereas you are forced to use Windows for .NET

Most of Java applications are built on open source tools but this is not the case with .NET.

With Java EE you are  vendor-neutral.  Java EE apps are extremely portable. Java EE is not even dependent on Sun Microsystems as it was developed by all major vendors.