When loading a domain object using hibernate and not modifying it, do I still need to define a spring transaction at the service layer?

I am currently learning Spring and Hibernate and have a question on transactions:

If I have an example DAO as follows:

@Override
public DatabaseObject getDatabaseObject(int id) {
   Session session = sessionFactory.getCurrentSession();

   return (DatabaseObject) session.createCriteria(DatabaseObject.class).add(Restrictions.eq("example", 3)).uniqueResult();
}

And in my service layer I have an example method

@Override
public int someBusinessLogic(int number) {
   DatabaseObje开发者_运维技巧ct object = dao.getDatabaseObject(number);
   //some business logic none of which modifies my databaseobject
}

Do I need to make someBusinessLogic transactional, and if so why?

You can get away without an explicit transaction but you will run into Exceptions if you have lazy relationships/collections from the DatabaseObject and try to access them.