One should refer the user to the official java.util.stream package (Stream API) documentation.
First appearance of the API in Java 8 (March 2014):
Description of the API in Java 18 (March 2022), as used for the book examples:
Latest description that is not “early access” is for Java 20 (March 2023):
There is a lot of information and caveats that is quite useful to be aware of: Parallelism, non-interference, Stateless behaviors, Side-effects. Ordering,