Sorting Elements in a TreeMap

import java.util.Iterator; import java.util.Map; import java.util.TreeMap; public class DiameterMap { public static void main(String args[]) { String names[] = { "Mercury", "Venus", "Earth", "Mars", "Jupiter", "Saturn", "Uranus", "Neptune", "Pluto" }; float diameters[] = { 4800f, 12103.6f, 12756.3f, 6794f, 142984f, 120536f, 51118f, 49532f, 2274f }; Map map = new TreeMap(); for (int i = 0, n = names.length; i < n; i++) { map.put(names[i], new Float(diameters[i])); } Iterator it = map.keySet().iterator(); Object obj; while (it.hasNext()) { obj = it.next(); System.out.println(obj + ": " + map.get(obj)); } } }