Java Program to convert HashMap to TreeMap

To convert HashMap to TreeMap, let us first create a Map with key-value pair −

Map<String, String>map = new HashMap<String, String>();
map.put("1", "A");
map.put("2", "B");
map.put("3", "C");
map.put("4", "D");
map.put("5", "E");
map.put("6", "F");
map.put("7", "G");

Now, convert the above HashMap to TreeMap −

Map<String, String>sorted = new TreeMap<String, String>(map);

Example

 Live Demo

import java.util.HashMap;
import java.util.Map;
import java.util.TreeMap;
public class Demo {
   public static void main(String[] a) {
      Map<String, String>map = new HashMap<String, String>();
      map.put("1", "A");
      map.put("2", "B");
      map.put("3", "C");
      map.put("4", "D");
      map.put("5", "E");
      map.put("6", "F");
      map.put("7", "G");
      map.put("8", "H");
      map.put("9", "I");
      Map<String, String>sorted = new TreeMap<String, String>(map);
      System.out.println("Sorted Map = "+sorted);
   }
}

Output

Sorted Map = {1=A, 2=B, 3=C, 4=D, 5=E, 6=F, 7=G, 8=H, 9=I}