You should never try to guess the rationale behind an interviewer's question. Once you're sure you understand the question and the information the interviewer is looking for, you should answer as straightforwardly and truthfully as possible. While the interviewer is trying to determine if you are the best candidate for this position, you are trying to understand if this job is right for you. If your answers uncover a difference of opinion, it may indicate that there's a potential for conflict after you are hired.

"Enum provides a quick shortcut to implement the Singleton design pattern. Enum Singleton is a promising technology since it can handle many programming tasks. These include creating a controlled instance, providing safe serialization safety, and creating thread-safe Singleton. It also eliminates the need to be concerned about double-checking locking and volatile variables."