Teeing, a hidden gem in the Java API

Last week, I described a use-case for a custom Stream Collector. I received a intriguing comment on Twitter: Interesting article. For completness' sake this specific problem could also be solved using the standard teeing collector— Miguel Martins (@Miguucm) May 3, 2021 Hats off to you, Miguel! Your comment revealed a method I didn’t know! So I decided to investigate what is the teeing() method about. Returns a Collector that is a composite of two downstream collectors.