Java stream поиск по возрасту во вложенных списках

List<People> listPeople1 = countryList.stream().forEach(p -> p.getPeopleList().stream().filter(q -> q.getAge() > 28).collect(Collectors.toList()));

import java.util.List;
 
public class Country {
 
    private List<People> peopleList;
    private String nameCountry;
 
    public Country(String nameCountry) {
        this.nameCountry = nameCountry;
    }
 
    public List<People> getPeopleList() {
        return peopleList;
    }
 
    public void setPeopleList(List<People> peopleList) {
        this.peopleList = peopleList;
    }
 
    public String getNameCountry() {
        return nameCountry;
    }
 
    public void setNameCountry(String nameCountry) {
        this.nameCountry = nameCountry;
    }
 
    @Override
    public String toString() {
        return "Country{" +
                "peopleList=" + peopleList +
                ", nameCountry='" + nameCountry + '\'' +
                '}';
    }
}

public class People {
 
    private String name;
    private int age;
 
    public People(String name, int age) {
        this.name = name;
        this.age = age;
    }
 
    public String getName() {
        return name;
    }
 
    public void setName(String name) {
        this.name = name;
    }
 
    public int getAge() {
        return age;
    }
 
    public void setAge(int age) {
        this.age = age;
    }
 
    @Override
    public String toString() {
        return "People{" +
                "name='" + name + '\'' +
                ", age=" + age +
                '}';
    }
}

import java.util.ArrayList;
import java.util.List;
import java.util.stream.Collectors;
 
public class Main {
 
    public static void main(String[] args) {
        List<Country> countryList = new ArrayList<>();
        Country country1 = new Country("USA");
        List<People> peopleList1 = new ArrayList<>();
        peopleList1.add(new People("Kevin", 27));
        peopleList1.add(new People("Arnold", 28));
        peopleList1.add(new People("Serg", 35));
        country1.setPeopleList(peopleList1);
        Country country2 = new Country("Russia");
        List<People> peopleList2 = new ArrayList<>();
        peopleList2.add(new People("Aleksey", 40));
        peopleList2.add(new People("Fedor", 37));
        peopleList2.add(new People("Ivan", 25));
        country2.setPeopleList(peopleList2);
        Country country3 = new Country("Germany");
        List<People> peopleList3 = new ArrayList<>();
        peopleList3.add(new People("Vander", 38));
        peopleList3.add(new People("Arkin", 18));
        peopleList3.add(new People("Philip", 25));
        country3.setPeopleList(peopleList3);
        countryList.add(country1);
        countryList.add(country2);
        countryList.add(country3);
 
        List<People> listPeople1 = countryList.stream().forEach(p -> p.getPeopleList().stream().filter(q -> q.getAge() > 28).collect(Collectors.toList()));
    }
}

countryList.stream()
                .map(Country::getPeopleList)
                .flatMap(Collection::stream)
                .filter(x -> x.getAge() > 28)
                .forEach(System.out::println);

List<People> listPeople1 = countryList.stream().map(Country::getPeopleList).flatMap(List::stream).filter(p -> p.getAge() > 28).collect(Collectors.toList());

countryList.stream()
                .filter(country -> country.getPeopleList()
                                        .stream()
                                        .allMatch(people -> people.getAge() > 28))
                .forEach(System.out::println);

.flatMap(country -> country.getPeopleList().stream())

List<People> listPeople1 = countryList.stream()
                .map(Country::getPeopleList)
                .flatMap(Collection::stream)
                .filter(x -> x.getAge() > 28).collect(Collectors.toList());