How to sort by two fields in Java?

Question

I have array of objects person (int age; String name;).

How can I sort this array alphabetically by name and then by age?

Which algorithm would

Answer 1

I'm not sure if it's ugly to write the compartor inside the Person class in this case. Did it like this:

public class Person implements Comparable  {

    private String lastName;
    private String firstName;
    private int age;

    public Person(String firstName, String lastName, int BirthDay) {
        this.firstName = firstName;
        this.lastName = lastName;
        this.age = BirthDay;
    }

    public int getAge() {
        return age;
    }

    public String getFirstName() {
        return firstName;
    }

    public String getLastName() {
        return lastName;
    }

    @Override
    public int compareTo(Person o) {
        // default compareTo
    }

    @Override
    public String toString() {
        return firstName + " " + lastName + " " + age + "";
    }

    public static class firstNameComperator implements Comparator {
        @Override
        public int compare(Person o1, Person o2) {
            return o1.firstName.compareTo(o2.firstName);
        }
    }

    public static class lastNameComperator implements Comparator {
        @Override
        public int compare(Person o1, Person o2) {
            return o1.lastName.compareTo(o2.lastName);
        }
    }

    public static class ageComperator implements Comparator {
        @Override
        public int compare(Person o1, Person o2) {
            return o1.age - o2.age;
        }
    }
}
public class Test {
    private static void print() {
       ArrayList list = new ArrayList();
        list.add(new Person("Diana", "Agron", 31));
        list.add(new Person("Kay", "Panabaker", 27));
        list.add(new Person("Lucy", "Hale", 28));
        list.add(new Person("Ashley", "Benson", 28));
        list.add(new Person("Megan", "Park", 31));
        list.add(new Person("Lucas", "Till", 27));
        list.add(new Person("Nicholas", "Hoult", 28));
        list.add(new Person("Aly", "Michalka", 28));
        list.add(new Person("Adam", "Brody", 38));
        list.add(new Person("Chris", "Pine", 37));
        Collections.sort(list, new Person.lastNameComperator());
        Iterator it = list.iterator();
        while(it.hasNext()) 
            System.out.println(it.next().toString()); 
     }  
}