HI !
We have a requirement our client wants us to persist the data in to a persistent storage using hibernate obviously if backend storage system is a database it is very easy to do in hibernate.
But our client’s requirement is to persist the data in a file system using hibernate so that in future if they decide to change the storage layer to a database it wont be any problem for them .
It looks pity confusing  but we really need to do that .
Can anyone please guide me is there any open source SDK for hibernate available which can do such thing for us .Or even can hibernate itself do that because we couldn’t find anything like that as a hibernate facility.
Any links to the pages which can help me solve this problem will be appreciated.

I guess you could try a text/csv JDBC driver. There are a couple around, but I have had no experience with them.

I have found one open source text/csv JDBC driver on sourceforge i think i also need the dialect in hibernate to communicate with this "text/csv JDBC driver" do you know about any open source dialect available for this purpose.

You will have to write the dialect yourself as far as I know. They are not that hard to write if you have the specifications of the driver. Check out the source for any of the packaged dialects in Hibernate.