This method will find the changes that had happened in the modifiedDoc Document object given the designated original Document.
Note that this process may need the knowledge of the conversion process since some conversion process are lossy. Items/Data that are lost during the conversion process are not classified as changes. The main target of this method is to apply the changes done in modifiedDoc into the assigned original Document object, thus it also will try to preserve items that were originally in the original Document, but never got transferred during the {@link org.openoffice.xmerge.DocumentSerializer#serialize serialize} process/method call. After this method call, theoriginal Document object will contain the changes applied.
This method may or may not be thread-safe. Also, it is expected that the user uses only one instance of a DocumentMerger object per merge process. Create another DocumentMerger object for another merge process.
@param modifiedDoc device
Document object.
@throws MergeException If any merge error occurs.