public class Home_work_All_Collections {

    public static void main(String[] args) {

        User user = new User("C", 6, true);
        User user1 = new User("D", 7, true);
        LinkedList<User> list = new LinkedList<>();
        list.add(user);
        list.add(user1);
        for (User list1 : list) {
            System.out.println(list1);
        }
    }
}

import java.util.Objects;

public class User implements Comparable<User> {

    private String name;
    private int age;
    private boolean activated;

    public User() {
    }

    public User(String name, int age, boolean activated) {
        this.name = name;
        this.age = age;
        this.activated = activated;
    }

    public boolean isActivated() {
        return activated;
    }

    public void setActivated(boolean activated) {
        this.activated = activated;
    }

    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 int hashCode() {
        int hash = 7;
        hash = 79 * hash + Objects.hashCode(this.name);
        hash = 79 * hash + this.age;
        hash = 79 * hash + (this.activated ? 1 : 0);
        return hash;
    }

    @Override
    public boolean equals(Object obj) {
        if (obj == null) {
            return false;
        }
        if (getClass() != obj.getClass()) {
            return false;
        }
        final User other = (User) obj;
        if (!Objects.equals(this.name, other.name)) {
            return false;
        }
        if (this.age != other.age) {
            return false;
        }
        if (this.activated != other.activated) {
            return false;
        }
        return true;
    }

    @Override
    public String toString() {
        return "User{" + "name=" + name + ", age=" + age + ", activated=" + activated + '}';
    }

    @Override
    public int compareTo(User o) {
        int res = name.compareTo(o.getName());
        if (res == 0) {
            if (age < o.getAge()) {
                return -1;
            }
            if (age > o.getAge()) {
                return 1;
            }if(age == 0){
                if(activated == true){
                    return 1;
                }else
                    return -1;
            }

        }
        return res;
    }

}