` package com.rowan.stream;
import java.util.ArrayList; import java.util.Arrays; import java.util.List; import java.util.stream.Collectors;
public class Test {
public static void main(String[] args) {
List<String> list = Arrays.asList("hello", "world", "stream");
list.stream().map(item -> item + item).collect(Collectors.toList()).forEach(System.out::println);
list.stream().map(item -> item + item).collect(
ArrayList::new,
(list1, value) -> list1.add(value),
(list1, list2) -> list1.addAll(list2)
).forEach(System.out::println);
list.stream().map(item -> item + item).collect(Collectors.toMap(p -> p, p -> p)).forEach((key, value) -> {
});
}
}
`
