We have a rich client application in Java that runs either in a
connected or disconnected mode. This application needs to consume an
ASP .Net web serivce, which is a challenge when the app is running
without network connection.

If the client is in .Net, I might be able to take advantage of Smart
Client Offline App Block by Microsoft. But the client is in Java.

I am thinking about creating a Java component that downloads the data
the service would otherwise provide to a local file and provides some
functions to retrieve them. Then Java client has to detect if service
is available and use live service if it is available and local Java
component if service not available. It is very possible that soon a
..Net client application will be in the same situation that I am in now.
Then we'll end up with a .Net component too, sort of defeats the
purpose of SOA. From service provider's point of view, they would like
to provide one things that allows clients of different platform to
retrieve data offline. Is there a way it can be done?

What would be my best approach? Thanks.