Java is a programming language with many language features, specifications, and APIs. Even among experienced Java developers, being aware of all of these is quite rare. If a study were conducted, we might come across Java developers who have never worked with Threads, never used JPA, or never developed custom annotations. However, is there a Java developer who has worked with Java 8 or later but has never used the Stream API? I highly doubt it.

Gatherers is a powerful extension of the Stream API that introduces support for customized intermediate operations. Initially introduced as a preview feature in JDK 22, it became a standard feature in JDK 24.