code: public static <T> Paging<T> flattenPaging(Collection<Paging<T>> collectionOfPaging)
  	{
  		if (collectionOfPaging == null || collectionOfPaging.isEmpty())
  			return null;
  
  		PageCriteria pageCriteria = null;
  		// get first page criteria
  		Paging<T> firstPaging = collectionOfPaging.iterator().next();
  
  		if (firstPaging != null)
  			pageCriteria = firstPaging.getPageCriteria();
  
  		return flattenPaging(collectionOfPaging, pageCriteria, null, null);
  
  	}
docs: Aggregates multiple collections into a single paging collection
  
  @param collectionOfPaging
  the collection paging that
  @param <T>
  the type class
  @return the flatten collections into a single collection