Streams: three-argument Stream.iterate replaces a for loop

Java 9 gave Stream.iterate a predicate, so a bounded sequence no longer needs a separate limit() call.

Code

List<Integer> powers = Stream.iterate(1, n -> n <= 64, n -> n * 2).toList();
System.out.println(powers);

String countdown = Stream.iterate(5, n -> n > 0, n -> n - 1)
        .map(String::valueOf)
        .collect(Collectors.joining(" -> "));
System.out.println(countdown);

Output

[1, 2, 4, 8, 16, 32, 64]
5 -> 4 -> 3 -> 2 -> 1

Run this yourself in the Online Java Compiler, spin up a live REST API in the API Sandbox, or practise with Java interview questions.

Published 2026-07-30