import java.util.stream.IntStream; class Main { public static void main(String[] args) { FibStream.stream().limit(41).forEachOrdered(System.out::println); } private static class FibStream{ private static int last = 0, next = 1; // fib(0), fib(1) private static IntStream stream(){ return IntStream.generate(() -> { int oldLast = last; last = next; next = oldLast + next; return oldLast; }); } } }