Worse case time complexity put/get HashMap

Question

What is the worst case time complexity of an Hashmap when the hashcode of it\'s keys are always equal.

In my understanding: As every key has the same hashcode it will al

Answer 1

In Java 8's HashMap implementation:

Handle Frequent HashMap Collisions with Balanced Trees: In the case of high hash collisions, this will improve worst-case performance from O(n) to O(log n).

From here.