Java8-Stream-No.08

import java.util.Arrays;import java.util.stream.IntStream;import java.util.stream.Stream;public class Streams8 {    public static void main(String[] args) {        Arrays.asList("a1", "a2", "a3")            .stream()            .findFirst()            .ifPresent(System.out::println);        Stream.of("a1", "a2", "a3")            .map(s -> s.substring(1))            .mapToInt(Integer::parseInt)            .max()            .ifPresent(System.out::println);        IntStream.range(1, 4)            .mapToObj(i -> "a" + i)            .forEach(System.out::println);        Arrays.stream(new int[] {1, 2, 3})            .map(n -> 2 * n + 1)            .average()            .ifPresent(System.out::println);        Stream.of(1.0, 2.0, 3.0)            .mapToInt(Double::intValue)            .mapToObj(i -> "a" + i)            .forEach(System.out::println);    }}