Lambda expression to check even numbers I wrote this code to check the even numbers from the List. After finding even number I twice the even numbers with the help of Map and then find the sum of each even number after making it double by use of the reduce method.

import java.util.Arrays;
import java.util.List;

public static void main(String[] args) {
List&lt;Integer&gt; numbers = Arrays.asList(1, 2, 3, 4, 5, 6, 7, 8, 9);

System.out.println(
numbers.stream()
        .filter(e -&gt; e % 2 == 0)
        .map( e -&gt; e * 2)
        .reduce(0, Integer::sum));
}
Have you come across the IntStream?  I'd use that for numerical operations rather than the boxed version Stream&lt;Integer&gt;.