In general we use italicized names to refer to entities in the MPI language independent procedure definitions, and typewriter font for concrete Java entities.
As a rule Java argument names are the same as the corresponding language independent names. In instance methods of Comm, Status, Request, Datatype, Op or Group (and subclasses), the class instance generally stands for the argument called comm, status, request, datatype, op or group, respectively in the language independent procedure definition.