stream API

lz-evaluate.java

public void lazyEvaluate() {
        List<Integer> numbers = List.of(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);

        long count = numbers.stream()
                .filter(n -> {
                    System.out.println("Filtering: " + n);
                    return n % 2 == 0;
                })
                .map(n -> {
                    System.out.println("Mapping: " + n);
                    return n * 2;
                })
                .peek(n -> System.out.println("Peeking: " + n))
                .collect(Collectors.counting());

        System.out.println("Total count of even numbers: " + count);
}