Java tutorial
import java.util.Calendar; import java.util.Locale; import java.util.Map; import java.util.NavigableMap; import java.util.TreeMap; public class NavigableMapSample { public static void main(String args[]) { Calendar now = Calendar.getInstance(); Locale locale = Locale.getDefault(); Map<String, Integer> names = now.getDisplayNames(Calendar.DAY_OF_WEEK, Calendar.LONG, locale); NavigableMap<String, Integer> nav = new TreeMap<String, Integer>(names); System.out.printf("Whole list:%n%s%n", nav); System.out.printf("First key: %s\tFirst entry: %s%n", nav.firstKey(), nav.firstEntry()); } }