Final answer:
Rehashing is the process that occurs when the load factor of a HashSet is breached. It involves creating a new, larger array and redistributing elements to maintain efficiency and performance.
Step-by-step explanation:
When the load factor of a HashSet is breached, the process that occurs is rehashing. The load factor is a measure that decides when the HashSet should be rehashed, which means that a new, larger array is created, and all existing entries are placed into the new array. This process is necessary to maintain the HashSet's performance, as an overloaded HashSet can lead to long chains in the buckets, which in turn leads to longer search times. When rehashing occurs, the hash function will likely distribute the elements more uniformly across the new array, therefore reducing the likelihood of collisions and maintaining average constant-time complexity for operations such as add, remove, and contains.