JuniorTheoryCommon

What does the program print?

JAVA

import java.util.List;

public class Main {
    public static void main(String[] args) {
        List<Integer> xs = List.of(1, 3, 5);
        int r = xs.stream()
            .filter(x -> x % 2 == 0)
            .findFirst()
            .orElse(-1);
        System.out.println(r);
    }
}

-1

Expecting 0: an empty Optional has no value of its own, not even zero; orElse(-1) returns the fallback that was passed to it.
Expecting a NoSuchElementException: only get() throws on an empty Optional, while orElse returns the fallback.

What would findFirst().get() do in this program?
What does the program print for the list List.of(1, 4, 6)?

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JuniorTheoryCommon

What does the program print?

JAVA

import java.util.List;

public class Main {
    public static void main(String[] args) {
        List<Integer> xs = List.of(1, 3, 5);
        int r = xs.stream()
            .filter(x -> x % 2 == 0)
            .findFirst()
            .orElse(-1);
        System.out.println(r);
    }
}

-1

Expecting 0: an empty Optional has no value of its own, not even zero; orElse(-1) returns the fallback that was passed to it.
Expecting a NoSuchElementException: only get() throws on an empty Optional, while orElse returns the fallback.

What would findFirst().get() do in this program?
What does the program print for the list List.of(1, 4, 6)?

Back to questions Open topic in roadmap →Answer it yourself — Quiz