The TreeMap in Java is used to implement Map interface and NavigableMap along with the Abstract Class. The map is sorted according to the natural ordering of its keys, or by a Comparator provided at map creation time, depending on which constructor is used.
To create TreeMap we can use Map class or TreeMap class reference.
Example 1:
Java
// Java program demonstrate how to create a TreeMap  import java.util.*;  class GFG {      public static void main(String[] args)    {        // Declaring a treemap        TreeMap<Integer, String> map;          // Creating an empty TreeMap        map = new TreeMap<Integer, String>();          System.out.println("TreeMap successfully"                           + " created");    }} |
Output
TreeMap successfully created
Example 2:
Java
// Java program demonstrate how to create and add elements// to TreeMap  import java.util.*;  class GFG {    public static void main(String[] args)    {        // Creating an empty TreeMap using Map interface        Map<Integer, String> map = new TreeMap<>();                System.out.println("TreeMap successfully"                           + " created");          // Adding elements        map.put(1, "Geeks");        map.put(2, "for");        map.put(3, "Geeks");          // Printing TreeMap        System.out.println("TreeMap: " + map);    }} |
Output
TreeMap successfully created
TreeMap: {1=Geeks, 2=for, 3=Geeks}
