eBay API reviseItem call using Java SDK

I have two ItemType objects: oldItem and newItem. I would like to Revise the oldItem to reflected changes in the newItem. To do this I assume after reading the documentation that we need to provide a list of removed/deleted fields.

Can anyone suggest an efficient way to go through all the fields (that can be changed) in the newItem, compare it to the oldItem and then actually come up with a string array of fields that was removed in the revision. And perhaps return and empty array of strings if no field was deleted.

PS. Let me know if my initial assumption about providing eBay with a list of deleted fields is incorrect. If that is incorrect then I am gonna have a much easier time revising items through the API.