Java Lambda Expressions Interview Questions

What is the main purpose of lambda expressions in Java?

Which is the correct syntax for a lambda expression that takes two integers a and b and returns their sum?

Which annotation is used to mark a functional interface in Java?

What will this code print?

interface Say {
    void speak(String msg);
}
public class Test {
    public static void main(String[] args) {
        Say s = (msg) -> System.out.println("Hello " + msg);
        s.speak("Java");
    }
}

What will happen?

public class Test {
    public static void main(String[] args) {
        Thread t = new Thread(() -> System.out.println("Thread running"));
        t.start();
    }
}

What will this code print?

import java.util.*;
public class Test {
    public static void main(String[] args) {
        List<String> list = Arrays.asList("A", "B", "C");
        list.forEach(s -> System.out.print(s + " "));
    }
}

Which is a valid method reference in Java?

Which statement about lambda expressions is true?

What will this code print?

import java.util.*;
public class Test {
    public static void main(String[] args) {
        List<Integer> nums = Arrays.asList(1, 2, 3, 4);
        nums.stream().filter(n -> n % 2 == 0).forEach(System.out::print);
    }
}

Which lambda correctly sorts a list of strings by length?