I have a stand alone application which is having swing as front end and an app server at the backend.What patttern is it and which best describes this pattern?I am not using JSPs(Obviously since my clients are stand alone).Can I use session beans?If so how and why?

Of course, MVC. People seem to have a wrong notion that MVC is only when you have JSPs :-). It is not. MVC is a core architectural pattern falling into the category of Interactive Systems Architecture. So what you have is MVC as well.

Whether to have sessions beans or not - I am sure, you have given too less an information to respond on that. But just because your front end is SWING does not mean you should not use it though.

-Sanjay

As long as you don't implement the core business logic in your View tier (Swing) you are fine. It should be done in your Model tier.

Thanks,
Senthil.

Of course, MVC. People seem to have a wrong notion that MVC is only when you have JSPs :-). It is not. MVC is a core architectural pattern falling into the category of Interactive Systems Architecture. So what you have is MVC as well. Whether to have sessions beans or not - I am sure, you have given too less an information to respond on that. But just because your front end is SWING does not mean you should not use it though.-Sanjay

suer.pattern is no limited in softwares.

The main reason for using swing as the front-end is to create fat-client applications, where a lot of business logic can be deferred to the front-end. This saves a lot of processing power on the server (app servers are known for their memory hogging traits). So even if the business logic is implemented on the front-end, but using relevant controllers or controlling sub-systems, you would have enough degree of decoupling to be treated as MVC. But if your view doesn't represent the Model,i.e., your presentation tier is not driven by the data state of the application, you are not following MVC dictat, which is also alright as MVC is not the only way to create an application.
This answer is fairly generic, so you have to see how your application is behaving to be able to ascertain if its MVC or not.

I have a stand alone application which is having swing as front end and an app server at the backend.What patttern is it and which best describes this pattern?I am not using JSPs(Obviously since my clients are stand alone).Can I use session beans?If so how and why?

This is MVC provided you do not have any business Logic in your Swing Component. Rather these components are just to provide the view (just like JSP's) to the user.
You can use Service Locator + Session Facade till you reach your Bean Instance and then from there on you can user any of the J2EE patterns based on your system needs.

In fact you can also J2EE Application Container services on the swing side.

One more value addition will be implementing the single signon model.

Hope this helps.