When to choose for webservice and what about the security?

[M.K.A. Monster]

Hello everyone,
I've been put on a project recently. It is my duty to design and build a webapplication, it's a pretty simple application. As I've been looking at it, it can be built with only the use of servlets and jsp. But after a chat with the manager he told me that he wanted to put in the folowing technologies: EJB, XML and WebServices.
Just because he wants that those technologies are used, I said: "I will use EJB, but it will be an enormous overhead, the important feature of EJB, scalability isn't in a need for this application."
But because I'm in a learning fase, this would be the ideal moment to learn more about EJB. But I was thinking about how to make it possible to implement some functionality in a Webservice.
I just have to say, the whole application will be on a one Borland Enterprise AppServer. I thought thas this appserver has all the needed functionality on board. Please correct me if I'm wrong!
Just on the way of the thinking about webservices, I thought it was only interesting to use, when there is a functionality/service available which will be shared among different applications. When I'm will implement one or more functionalities of this webapp using a webservice, I only see an overhead in front of me.
Making a request to a webservice:
- Packing the XML request document.
- Unpacking the XML request document.
- Processing the request
- Packing the XML response document.
- Unpacking the XML response document.
When everything is done on one server, as I explained above, this would be an overhead for 4 of 5 steps. Off course the processing will be a heavier step than the others.
I don't think I should use a webservice in this project. But can anyone explain me, when I should use a webservice?
Just when I will have to use a webservice, I don't think I have to implement any security functionality, because it all is on the same machine/server. But at what point should I get thinking about security matters though?
I hope someone can correct me in some at some points if nescasary.
Regards,
Mark Monster

[Lasse Koskela]

*sigh* I had almost forgotten these types of managers exist...
From what you said, I can't think of any reason to use Web Services. However, if your application has some functionality that others might use in the future, maybe that functionality could be made available through a Web Service.
Would it perhaps be possible to give your manager a brief introduction to the concept of Web Services and what they're good for (without getting laid off or losing a promotion)?
As you said, Web Services bring certain overhead and if the functionality provided by a Web Service will only be used locally within a single application, there is no reason other than "getting to use some cool technology" or "extending your skillset".