Java Stream How to - Compare forEach implementation

• Back to Stream  ↑

Question

We would like to know how to compare forEach implementation.

Answer

/*from  w  ww  . j a v a  2  s  .c o  m*/
import java.util.Arrays;
import java.util.List;

public class Main {
    public static void main(String[] args) {

        List<String> friends = Arrays.asList("A", "B", "C", "D");

        //external iterate with index == evil
        for(int i = 0; i < friends.size(); i++) {
            System.out.println(friends.get(i));
        }

        //external iterate on collection, better but ... external
        for(String friend : friends){
            System.out.println(friend);
        }

        //lambda
        friends.forEach(s -> System.out.println(s));

        //lambda reference
        friends.forEach(System.out::println);
    }

}

The code above generates the following result.

• Back to Stream  ↑