InterF.java

// EMD-InterF/InterF.java
 
import java.util.Arrays;

class Person {

    private String name;
    private int    year;

    public Person(String name, int year) {
        this.name = name;
        this.year = year;
    }

    public String getName() { return name; }
    public int getYear()    { return year; }

    @Override
    public String toString() {
        return name + "(" + year + ")";
    }

    static void show(Person[] persons, String message) {
        System.out.println(message);
        for (Person person : persons)
            System.out.print(person + " ");
        System.out.println();
    }
}

public class InterF {

    public static void main(String[] args) {
        Person[] persons =
            { new Person("Mary",1990),
              new Person("Joan",1992),
              new Person("Suzy",1992),
              new Person("Beth",1992),
              new Person("Suzy",1980),
              new Person("Katy",1982), };
        Person.show(persons,"At the beginning:");

          // lambda as a single expression -
          // no return, no semicolon
        Arrays.sort(persons,
            (p1, p2) -> p1.getYear()-p2.getYear());
        Person.show(persons, "Ordered by age");

          // lambda as a compound statement -
          // return and semicolons, as usually
        Arrays.sort(persons, (p1, p2) ->
            {
                int d = p1.getName().compareTo(p2.getName());
                if (d != 0) return d;
                return p1.getYear() - p2.getYear();
            });
        Person.show(persons,"Ordered by name then age");
    }
}