Which class does not belong to virtual

hello Sir,
i have a doubt in UVM most of the classes are virtual so i like to know which class is does not belong to virtual, kindly give some suggestions

In reply to l@kshm@n:
Virtual classes are never constructed. They are the foundations, or base classes for your classes. They have no use without extending them first. The umm_tlm_fifo is an example of a class that is not virtual. It is ready to be used without being extended first.

In reply to dave_59:

Thank you sir