Question 40 in chapter 9 (OCP 17 - Practice Tests) - Possible alternative case

[Karl J Balder]

The question asks to assume that '/all-data' exists and is accessible, but does that not still leave the possibility that it is not a directory? In which case Files.list would throw an exception.

The provided answer states that the code compiles and runs without issue.

40. What is the output of the following application? Assume /all-data exists and is accessible within the file system.

    public static Stream<String> readLines(Path p) {
        try { return Files.lines(p); } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    public static long count(Path p) throws Exception {
        return Files.list(p)
                .filter(w -> Files.isRegularFile(w))
                .flatMap(s -> readLines(s))
                .count();
    }

    public static void main(String[] d) throws Exception {
        System.out.println(count(Paths.get("/all-data")));
    }

[Mikalai Zaikin]

Hello Karl .
You're right.
The question is a bit ambigous.
It must say that "all-data" is accessible and is a directory.
You not listed options, if it contains "May throw runtime exception", then it can be correct.

[Jeanne Boyarsky]

IT's not a It'a s choose one question though. So assuming it isn't a directory isn't the most likely case.