Abstract: The present invention relates to a middleware for data communication between legacy systems and clients via wired or wireless communication network. The middleware includes a business logic database for storing business logics, an object creating module for determining a legacy system with which a business logic operates and creating a business object for the business logic so that the business object can be handled by the legacy system, a business logic searching module for receiving a request for a business logic from a client and searching for the business logic in the business logic database, in case the business logic requested by the client exists in the business logic database, the business logic searching module returning the business object for the business logic created by the object creating module in response to the request, and an instance creating module for creating and returning an instance of the business object.