【stream_map】import java.util.Arrays;
import java.util.List;
public class Main {
public static void main(String[] args) throws Exception{
// map
List<String> words = Arrays.asList("Hello", "World");
words.stream()
.flatMap((String line) -> Arrays.stream(line.split("")))
.distinct()
.forEach(System.out::println);
}
}
