I have an object for storing "personal details (person)", during the user updation what I’m doing is using hql I’ll load the existing "person”, and then according to the user input the object will be modified. Before the object with new values is persisted, it is validated. If there are some errors I want the old object back (Peron with original values). For this purpose, if the is any error, I’ll load the "person" again.

At this point I’m facing a problem, the newly loaded object
is reflecting the changes made by the user ( the newly loaded "person" is supposed to be the one with values before updating, since the updated person is not persisted yet.).

Due to this, the user may get a feeling that the "person" is updated with wrong values, even if this is not the case. For my project I’m using Struts with Hibernate.
Please suggest a solution.

create a special class that will hold person data which you will validate (you could name PersonFormData) and then:

1. load Person object
2. transfer data to PersontFormData
3. edit PersonFormData
4. validate
5. if valid transform data from PersonFormData into Person object
6. persist Person

this way you will not have your persistent data model in inconsistent state.

You may want to look at cocoon forms (http://cocoon.apache.org/2.1/). There is a block called CForms which has it's own form model (no need to create PersonFormData class).