HashMap works on the principle of hashing, we have put(key, value) and get(key) method for storing and retrieving Objects from HashMap. When we pass Key and Value object to put() method on Java HashMap, HashMap implementation calls hashCode method on Key object and applies returned hashcode into its own hashing function to find a bucket location for storing Entry object, important point to mention is that HashMap in Java stores both key and value object as Map.Entry in a bucket which is essential to understand the retrieving logic.
If people fail to recognize this and say it only stores Value in the bucket they will fail to explain the retrieving logic of any object stored in Java HashMap. This answer is very much acceptable and does make sense that interviewee has a fair bit of knowledge on how hashing works and how HashMap works in Java. But this is just start of story and confusion increases when you put interviewee on scenarios faced by Java developers on day by day basis.