Rethinking Java Streams: Gatherer for more control and parallelism
Since version 8, Java has introduced an elegant, functional approach to processing data sets with the Streams API. The terminal operation collect(…) represents the bridge from the stream to a targeted aggregation - in the form of lists, maps, strings or more complex data structures. Until Java 20 the processing was done Collector-Instances were regulated, which internally consisted of a supplier, an accumulator, a combiner and optionally a finisher. This model works well for simple accumulations but has noticeable limitations, particularly for complex, stateful, or conditional aggregations.
