CODE EXAMPLE FOR JAVA

hash tree in java

/* Java program to print frequencies of all elements using 
   TreeMap */
import java.util.*;

class Main
{
    // This function prints frequencies of all elements
    static void printFreq(int arr[])
    {
        // Creates an empty TreeMap
        TreeMap<Integer, Integer> tmap =
                     new TreeMap<Integer, Integer>();

        // Traverse through the given array
        for (int i = 0; i < arr.length; i++)
        {
            Integer c = tmap.get(arr[i]);

            // If this is first occurrence of element   
            if (tmap.get(arr[i]) == null)
               tmap.put(arr[i], 1);

            // If elements already exists in hash map
            else
              tmap.put(arr[i], ++c);
        }

        // Print result
        for (Map.Entry m:tmap.entrySet())
          System.out.println("Frequency of " + m.getKey() + 
                             " is " + m.getValue());
    }

    // Driver method to test above method
    public static void main (String[] args)
    {
        int arr[] = {10, 34, 5, 10, 3, 5, 10};
        printFreq(arr);
    }
}