Removing items from a collection in java while iterating over it

Question

I want to be able to remove multiple elements from a set while I am iterating over it. Initially I hoped that iterators were smart enough for the naive solution below to wor

Answer 1

If you have enough memory for one copy of the set, I'll assume you also have enough memory for two copies. The Kafka-esque rules you cite don't seem to forbid that :)

My suggestion, then:

fillSet(set);
fillSet(copy);
for (Object item : copy) {
   if (set.contains(item)) { // ignore if not
     set.removeAll(setOfStuffToRemove())
   }
}

so copy stays intact and just provides the stuff to loop on, while set suffers deletions. Stuff that was removed from set in the meantime will be ignored.