>i have gone i java course lastdays. i couldn't learned java (it confused me) but i learned polymorphism. does vfp support polymorphism if answer yes how?

Yes it does.

"Use Access/Assign Methods for Polymorphism Sample

File: ...\Samples\Solution\Tahoe\Aa_outline.scx

This sample uses Access/Assign methods to demonstrate object polymorphism."

For another sample check Q132359 on MSDN help.
Cetin