How does HashSet behave when there are elements with the same hash code of keys?

HashSet in Java and Kotlin is based on a hash table and uses the hash code of elements for quick access. If multiple elements have the same hash code (collision), HashSet stores them in a single "bucket," usually as a linked list or a tree.

When adding a new element with a hash code that already exists, HashSet compares elements using the equals() method. If the element already exists, it is not added; otherwise, it is added to the bucket.

Thus, having identical hash codes does not lead to data loss but can degrade operation performance due to the need for sequential comparison of elements in the bucket.