Java tutorial
import java.util.Comparator; import java.util.NavigableMap; import java.util.TreeMap; public class Main { public static void main(String[] args) { TreeMap<Integer, String> treemap = new TreeMap<Integer, String>(); // populating tree map treemap.put(2, "two"); treemap.put(1, "one"); treemap.put(3, "three"); treemap.put(6, "six"); treemap.put(5, "from java2s.com"); // using comparator Comparator comp = treemap.comparator(); System.out.println("Following natural ordering"); System.out.println("Comparator value: " + comp); } }