import java.util.ArrayList; import java.util.Collections; import java.util.List; public class Main { public static void main(String[] args) { List europe = new ArrayList(); europe.add(new Country(81903000,357121.41,"Germany")); europe.add(new Country(64667000,668763, "France")); europe.add(new Country( 4985900,385199, "Norway")); europe.add(new Country( 9514406,450295, "Sweden")); europe.add(new Country(47212990,504645, "Spain")); europe.add(new Country( 8014000, 41285, "Switzerland")); europe.add(new Country( 36371, 2.02, "Monaco")); System.out.println(europe); Collections.sort(europe); System.out.println(europe); Collections.sort(europe, new PopulationDensityComperator()); System.out.println(europe); } }