NavigableSet by TreeSet : NavigableSet « Collections « Java Tutorial

1. Java Tutorial
2. Collections
3. NavigableSet

import java.util.NavigableSet;
import java.util.TreeSet;

public class CityNavigator {
  static NavigableSet<String> citiesSet;

  public static void main(String[] args) {
    String[] cities = { "A", "B", "C", "D", "E", "F" };

    citiesSet = new TreeSet<String>();
    for (String city : cities)
      citiesSet.add(city);


    for (String city : citiesSet)
      System.out.println("  " + city);
  }

}