Question

Is it safe to remove and add elements to ConcurrentSkipListSet while iterating over it:

ConcurrentSkipListSet<Element> set = new ConcurrentSkipListSet<Element>(myComparator);
for(Element e : set)
{
   if(condition)
   {
      set.remove(e);
      set.add(anotherE);
   }
}

where e and anotherE are equal by provided comparator.

Answer 1

Yes it is safe. From java docs:

Insertion, removal, and access operations safely execute concurrently
by multiple threads. Iterators are weakly consistent, returning
elements reflecting the state of the set at some point at or since the
creation of the iterator. They do not throw
ConcurrentModificationException, and may proceed concurrently with
other operations.