Computer scienceProgramming languagesJavaCode organizationFunctional programmingFunctional streams

Parallel streams

Theory

Prime numbers

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You need to create a prepared parallel LongStream for filtering prime numbers in the given range (inclusive both borders). After calling the count() method it should return the count of prime numbers in the given range. Pay attention to the method template.

The static method NumberUtils.isPrime(someLong) is already available for you. It returns true if the passed value is prime and false otherwise.

Please, be careful with the rangeClosed, iterate and limit methods!

PS: it's not a very efficient approach for generating prime numbers, it's just an example of parallel calculations with streams.

Write a program in Java 17
import java.util.Scanner;
import java.util.stream.*;

class ParallelFilteringStream {

public static LongStream createPrimesFilteringStream(long start, long end) {
// write your code here
return LongStream.of();
}

/* Please do not modify the code below */
public static void main(String[] args) {
final Scanner scanner = new Scanner(System.in);
final String[] vals = scanner.nextLine().split(" ");

final long left = Long.valueOf(vals[0]);
final long right = Long.valueOf(vals[1]);

final LongStream stream = createPrimesFilteringStream(left, right);

if (!stream.isParallel()) {
throw new RuntimeException(
"You need to write a parallel stream, not sequential!");
}

final Long count = stream.boxed().count();

System.out.println(count);
}

public static class NumberUtils {

public static boolean isPrime(long n) {
return n > 1 && LongStream
.rangeClosed(2, n - 1)
.noneMatch(divisor -> n % divisor == 0);
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