I was looking for an answer to the question of what a DAO should return when a search ends up to be for an entity that does not exist.
There are some generic previous questions related to returning null, but I am looking for an answer specifically in the context of the DAO retrieve scenario.
To be clear, when I say Null Object I am referring to the Null Object pattern. In the Java space, Josh Bloch recommends an empty collection solution in the book Effective Java (See Item 43) which provides an very good introduction to the problem/solution.
Despite being aware of Bloch's advice when I first wrote this question I considered returning null appropriate in a read/retrieval scenario. I'm in good company making a mistake with nulls.