Remote Method Invocation ‘s method factor has definition of property. You can use more than one for each parameter.

in	This mean, input type is factor. Current version only support “in”. It dose not support “out”. It is necessary.
byval	It means factor deliver to by value. If you use it “&” will be omissible in factor type at C++ proxy and stub. It is suitable for small form such as int or float.
mutable	It means, factor is not const type. If you use it const keyword will be omissible in factor form at C++ proxy and stub. It is suitable to change value of factor that assigned from RMI stub.

You can define property of method factor as followed.

For example, if you declare RMI method as followed

Foo([in,byval] int a, [in,mutable] String b, [in] float c);

C++ code will generated as followed.

Foo(HostID, RmiContext&, int a, String& b, const float& c);

Almost all case use [in] for factor property of RMI method.