java8 stream是可以過程中向對象中放東西的

 public static void main(String[] args) {
        List<Person> list = new ArrayList<>();
        Person person;
        for (int i = 0; i < 20; i++) {
            person = new Person();
            person.setName("person :" + String.valueOf(i));
            person.setAge(i);
            person.setHeight(Long.valueOf(i));
            person.setWeight(Double.valueOf(i));
            list.add(person);
        }
        list.parallelStream().forEach(father -> {
            Person child = new Person();
            child.setName("child");
            child.setAge(9);
            child.setHeight((long) 1.2);
            child.setWeight(59.00);
            List<Person> children = new ArrayList<>();
            children.add(child);
            father.setChildren(children);
        });
        list.spliterator().forEachRemaining(per -> System.out.println(per.getChildren()));
    

輸出
[Person{name=‘child’, age=9, height=1, weight=59.0, children=null}]
[Person{name=‘child’, age=9, height=1, weight=59.0, children=null}]
[Person{name=‘child’, age=9, height=1, weight=59.0, children=null}]
[Person{name=‘child’, age=9, height=1, weight=59.0, children=null}]
[Person{name=‘child’, age=9, height=1, weight=59.0, children=null}]
[Person{name=‘child’, age=9, height=1, weight=59.0, children=null}]
[Person{name=‘child’, age=9, height=1, weight=59.0, children=null}]
[Person{name=‘child’, age=9, height=1, weight=59.0, children=null}]
[Person{name=‘child’, age=9, height=1, weight=59.0, children=null}]
[Person{name=‘child’, age=9, height=1, weight=59.0, children=null}]
[Person{name=‘child’, age=9, height=1, weight=59.0, children=null}]
[Person{name=‘child’, age=9, height=1, weight=59.0, children=null}]
[Person{name=‘child’, age=9, height=1, weight=59.0, children=null}]
[Person{name=‘child’, age=9, height=1, weight=59.0, children=null}]
[Person{name=‘child’, age=9, height=1, weight=59.0, children=null}]
[Person{name=‘child’, age=9, height=1, weight=59.0, children=null}]
[Person{name=‘child’, age=9, height=1, weight=59.0, children=null}]
[Person{name=‘child’, age=9, height=1, weight=59.0, children=null}]
[Person{name=‘child’, age=9, height=1, weight=59.0, children=null}]
[Person{name=‘child’, age=9, height=1, weight=59.0, children=null}]

明顯是放進去了