Rethinking Java Streams: Gatherer for more control and parallelism

sven.ruppert@gmail.com (Sven Ruppert) — Wed, 02 Apr 2025 20:58:21 +0000

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.

Gatherer on Sven Ruppert

Rethinking Java Streams: Gatherer for more control and parallelism