We would like to build on java application using API which client suppose to provide. But Client asked to used existing jdk API indirectly I mean use one wrapper in between. So going ahead if client provides his own API that time without much change we should be able to use those. So please suggest how we can design inteface which will give us the flexibility...thnx
From what I understand of your description, it sounds like Adapter is a fit. But could you clarify who is providing what?
"client provides API" and "Client asked to  use one wrapper in between" are not clear to me...