Is there a Collector that collects to an order-preserving Set?
You can use toCollection and provide the concrete instance of the set you want. For example if you want to keep insertion order:
Set<MyClass> set = myStream.collect(Collectors.toCollection(LinkedHashSet::new));For example:
public class Test { public static final void main(String[] args) { List<String> list = Arrays.asList("b", "c", "a"); Set<String> linkedSet = list.stream().collect(Collectors.toCollection(LinkedHashSet::new)); Set<String> collectorToSet = list.stream().collect(Collectors.toSet()); System.out.println(linkedSet); //[b, c, a] System.out.println(collectorToSet); //[a, b, c] }}