I can appreciate trying to give the implementers some flexibility, but the exception is part of the API, so you should put some thought into what (checked) exception(s) makes sense.
By saying throws Exception, you are not helping the clients of the interface understand what kinds of failures are expected to give them a chance to react to them appropriately. You can consider akin to accepting a method parameter of Object to allow implementers to decide what arguments they can accept. Its good for the implementer, but a nightmare for the clients of the interface.
