प्रदर्शन-मापन

import java.util.*;public class Main {
  public static void main(String[] args) {
    List<Integer> nums = new ArrayList<>();
    for(int i=0;i<1_000_000;i++) nums.add(i);
    long start = System.currentTimeMillis();
    long sum = nums.stream().mapToLong(n -> n).sum();
    long time = System.currentTimeMillis() - start;
    System.out.println("Sequential sum=" + sum + " in " + time + "ms");
  }
}

import java.util.*;public class Main {
  public static void main(String[] args) {
    List<Integer> nums = new ArrayList<>();
    for(int i=0;i<1_000_000;i++) nums.add(i);
    long start = System.currentTimeMillis();
    long sum = nums.parallelStream().mapToLong(n -> n).sum();
    long time = System.currentTimeMillis() - start;
    System.out.println("Parallel sum=" + sum + " in " + time + "ms");
  }
}

import java.util.*;public class Main {
  public static void main(String[] args) {
    List<Integer> nums = new ArrayList<>();
    for(int i=0;i<1_000_000;i++) nums.add(i);
    long start = System.currentTimeMillis();
    double avg = nums.parallelStream().mapToInt(n -> n).average().orElse(0);
    long time = System.currentTimeMillis() - start;
    System.out.println("Parallel average=" + avg + " in " + time + "ms");
  }
}