Scanning of evacuated objects in a generation managed by the train algorithm

In computer systems including memory which execute programs of instructions, vtables associated with objects contain pointers which invoke operations to be performed by the program which are related to the objects. The operation invoked may include the step of modifying the pointer such that upon a subsequent reference to the vtable a different operation is invoked. In one embodiment, such vtables are utilized in conjunction with garbage collection methodologies such as those that invoke the train algorithm, such that operations such as reference processing, insertion and scanning during garbage collection may be invoked by pointers in vtables associated with cars or objects in the cars, and the vtables may invoke differing versions of the said operations depending on the characteristics and past history of the car or object, and upon an operation being executed the operation may change the pointer so that a different version of the operation is performed upon a subsequent reference to the vtable associated with the car or object.