Java Stream - 如何将列表字符串转换为大写

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

public class Main {

  public static void main(final String[] args) {
    List<String> friends = Arrays.asList("Ross", "Chandler", "CSS",
        "Monica", "Joey", "Rachel");

    friends.stream().map(name -> name.toUpperCase())
        .forEach(name -> System.out.print(name + " "));

  }

}