uvm_top.print_topology(); -
Print topology is used to print the entire TB hierarchical structure.It is called in the end_of_elaboration_phase() after the entire TB components are built.
factory.print();
factory creates the TB components and transaction objects and we can override the original type with a new type in the build_phase() before creating them.
If we override then factory.print will give u information about what overrides what.