Hi Kokila,
I'm not sure if I understand your problem correctly, but
struts 2 supports list of values in your action if you use indexes in your hidden fields. Basically you would need to submit your values to the action like this
list[0].firstname = Kokila
list[0].lastname = Mahadev
list[1].firstname = Ankit
list[1].lastname = Garg
That way Struts will make you a list of objects. You can use the syntax you are already using to generate hidden fields with that sort of names i.e. something like this