Is the time to find an element in a HashSet always the same regardless of the set size?

The average time to search for an element in a HashSet in Java is considered constant — O(1), meaning it does not depend on the size of the set. This is achieved by using a hash table, where the element is located by its hash code.

However, in practice, the search time can vary due to hash collisions, when multiple elements fall into the same bucket. In such cases, the search within the bucket can be linear in the number of elements in it.

With the introduction of Java 8, if a bucket contains too many elements, they are stored as a balanced tree (TreeNode), which improves the worst-case search time to O(log n).

In summary:

• On average, searching in a HashSet is — O(1)
• In the worst case — O(log n) (starting from Java 8)

Therefore, the search time is not always exactly the same, but for most practical purposes, it is efficient and fast.