The definition of the supported subset of Java Card RMI for the Java Card Platform, Version 2.2.2, implies functional limitations during the execution of Java Card API remote methods:
CAD client application remote objects cannot be passed as arguments to remote methods.
Card remote objects cannot be passed as arguments to remote methods.
Applets on the card cannot invoke remote methods on the CAD client.
Method argument data and return values, along with the Java Card RMI protocol overhead, must fit within the size constraints of an APDU command and APDU response, respectively.