1. A computer implemented method comprising: storing a configuration of at least one mapping relationship defining a correspondence between an attribute of an application programming interface (API) function of a heterogeneous enterprise information system (EIS) and an object of a cross-platform connection framework, the configuration comprising the at least one mapping relationship encoded in executable codes, the cross-platform connection framework comprising a software driver that couples the heterogeneous EIS with an application server; executing the executable codes in the application server to thereby install a persistent object from a memory on or accessible to the application server, the persistent object being installed between the application server and the cross-platform connection framework, the persistent object corresponding to a first data structure in the application server and comprising a stateful second data structure that includes a persistent field; configuring a parameter for a code generation service, the parameter mapping a first element type of the API function to a second element type within the stateful second data structure of the persistent object; and accessing the API of the EIS via the persistent object, the accessing comprising storing, in the persistent field of the persistent object, a value of a data element generated by activation of the API function, and retrieving the value of the data element from the persistent field of the persistent object for use by the application server.