The time complexity of Iterator() in java

Question

I am new to Java. I have a question about the time complexity of java iterator().

Set<Integer> set = new HashSet<>();

Iterator<Integer> iter = set.iterator(); ==> (2)

I wanna know what is the time complexity of step 2? It is const time O(1) or it depends on the size of set?

Thanks

Answer 1

Calling iterator() is constant time. It is a method call that returns an Iterator instance on the collection you are calling on. Actually iterating through the collection using the iterator using while (hasNext()) will be O(n)