Majority Element II

Given an integer array of size n, find all elements that appear more than ⌊ n/3 ⌋ times.
Note: The algorithm should run in linear time and in O(1) space.
Example 1:

Input: [3,2,3]
Output: [3]

Example 2:

Input: [1,1,1,3,3,2,2,2]
Output: [1,2]

import java.util.*;
public class NewClass7 {
    HashMap<Integer,Integer> ar=new HashMap<Integer,Integer>();
    public void majorityElement(int[] nums) {
        
        for(int i=0;i<nums.length;i++)
        {
            if(ar.containsKey(nums[i]))
            {
                ar.put(nums[i],ar.get(nums[i])+1);
            }else
            {
                ar.put(nums[i],1);
            }
        }
        for(int i:ar.keySet())
        {
            if(ar.get(i)>nums.length/3)
            {
               System.out.print(i+" ");
            }
        }
    }
    public static void main(String args[])
    {
        int ar[]={1,1,1,3,3,2,2,2};
        NewClass7 ob=new NewClass7();
        ob.majorityElement(ar);
    }
    
}