Java 7 and java 8 working with collection comparision. How to use void functions to affect objects. Lombok used for Objects that represents datas.

Car.java

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

@NoArgsConstructor
@AllArgsConstructor
public @Data class Car {
    private String type;
}

Java7Versus8.java

import java.util.ArrayList;
import java.util.List;

public class Java7Versus8 {

    public static void main(String[] args) {
        Java7Versus8 java7Versus8 = new Java7Versus8();
        java7Versus8.java7Version();
        java7Versus8.java8Version();
    }


    private void java8Version() {
        System.out.println("Java 8 version : ");
        List<User> data = getData();

        data.stream()
                .filter(user -> user != null)
                .forEach(user -> user.setName(user.getName() + "-plus"));

        data.stream()
                .filter(user -> user != null)
                .flatMap(user -> user.getCars().stream())
                .filter(car -> car != null)
                .forEach(car -> car.setType(car.getType() + "-minus"));

        data.stream()
                .forEach(System.out::println);
    }


    private void java7Version() {
        System.out.println("Java 7 version : ");
        List<User> data = getData();

        for (User user : data) {
            if (null == user) { continue; }
            user.setName(user.getName() + "-plus");
            for (Car car : user.getCars()) {
                if (null == car) { continue; }
                car.setType(car.getType() + "-minus");
            }
        }

        for (User user : data) {
            System.out.println(user);
        }
    }

    private List<User> getData() {
        List<User> users = new ArrayList<>();
        users.add(getUser("Peter"));
        users.add(getUser("Patrik"));
        users.add(getUser("Mario"));
        return users;
    }

    private User getUser(String name) {
        User user = new User(name, null);

        List<Car> carList = new ArrayList<>();
        carList.add(getCar("BMW"));
        carList.add(getCar("Audi"));
        carList.add(getCar("Skoda"));
        user.setCars(carList);
        return user;
    }

    private Car getCar(String name) {
        return new Car(name);
    }
}

User.java

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

import java.util.List;

@NoArgsConstructor
@AllArgsConstructor
public @Data class User {
    private String name;
    private List<Car> cars;
}