Java HashSet.stream() is a method in the Java HashSet class that returns a Stream of the set's elements. This method is useful for functional-style operations like filtering, mapping, or reducing the elements of a set. Introduced in Java 2014 with Java 8, stream() integrates sets with the Java Stream API for declarative data processing.

https://docs.oracle.com/javase/8/docs/api/java/util/HashSet.html