.Net Programming Language (VB.Net and C# are .Net language) is a Microsoft product which can be compiled to run on Microsoft .Net Framework on top of Windows platform. Windows Vista is pre-installed with .Net Framework 3.0 (at the time of writing, the latest .Net Framework is 3.5. It can be downloaded from Microsoft website free-of-charge). The design goal of .Net language is to provide a user-friendly language optimized for performance running on Microsoft Windows platform. If you are using Windows Server and you do not to intend to change to other type of server, .Net is a good choice.

Java Programming Language is a Sun Microsystems product which can be compiled to run on Java Virtual Machine (JVM) on top of any platform. JVM can be downloaded from Sun Microsystems website free-of-charge. It design goal is to provide a multi-platforms language. This language can be run on Windows as well as Unix platforms. If you are using Unix Server, Java is your choice. If you are using Windows Server, you can still use Java but .Net in this case seems to be a better choice because .Net is optimized on Windows platforms.

As .Net and Java are built on different technologies, they cannot talk to each other directly. Fortunately, they can talk to each other via XML Web Services because XML Web Service uses SOAP protocol that is supported by most vendors in the IT industry.