Java Coding Problems

192. Teeing

Starting with JDK 12, we can merge the results of two collectors via Collectors.teeing():

• public static <T,​R1,​R2,​R> Collector<T,​?,​R> teeing​(Collector<? super T,​?,​R1> downstream1, Collector<? super T,​?,​R2> downstream2, BiFunction<? super R1,​? super R2,​R> merger):

The result is a Collector that is a composite of two passed downstream collectors. Every element that's passed to the resulting collector is processed by both downstream collectors, and then their results are merged into the final result using the specified BiFunction.

Let's take a look at a classical problem. The following class simply stores the number of ...