The process of internalising an object involves internalising its data from a stream.
For a class instance, this involves internalising each of its data members and components from a stream in the same order that they were originally externalised. This process is encapsulated by the InternalizeL() member function of the class.
A class always defines InternalizeL() as:
void InternalizeL(RReadStream& aStream);
and uses the read stream interface class, RReadStream.
Note that InternalizeL() is not virtual and there is no implication that a class that requires an InternalizeL() function must be derived from any particular base class.