Why initialize HashSet<>(0) to zero?

Question

I love a HashSet<>() and use this eagerly while initializing this with the default constructor:

Set users = new HashSet<>();
         


        

Answer 1

If you see docs

There is some clue.

Iterating over this set requires time proportional to the sum of the HashSet instance's size (the number of elements) plus the "capacity" of the backing HashMap instance (the number of buckets). Thus, it's very important not to set the initial capacity too high (or the load factor too low) if iteration performance is important.