Summary

In this chapter, we described the middle tier and how it can benefit you from both performance and reusability points of view. We also showed you how to create a reusable component that can then be exposed through a Web Service and accessed from almost any application. We presented these important concepts in a relatively small space. We did so intentionally to show you just how simply they can actually be implemented without diving into which memory location gets called what when a Web request comes through.

Questions and Answers

Q1:	Can I call a .NET Web Service from Java?
A1:	Yes. Without showing a huge code sample, Java provides a java.net library that has functionality allowing you to connect to a URL, via HTTP, of a Web Service, running on the .NET platform, and then using Java's XML classes to parse the results.
Q2:	What about exposing Web Services through my firewall?
A2:	Web Services typically run on port 80 (the same as HTTP), so there are no special considerations from a system administration point of view. At the lowest level, a Web Service is really just a Web page that has no GUI. From a programming point of view, though, you may have to code for authentication methods as set by the Web server.