Intersection of Two Arrays II

class Solution {
    public int[] intersect(int[] nums1, int[] nums2) {
       return Common(nums1,nums2);
    }
    public static int []Common(int []arr1,int []arr2){
        HashMap<Integer,Integer> map = new HashMap<>();
        
        for(int i =0;i<arr1.length;i++){
             if(!map.containsKey(arr1[i])){
               map.put(arr1[i],1);  
             }
            else{
                map.put(arr1[i],map.get(arr1[i])+1);
            }
        }
       //Checking common and putting int arraylist
        ArrayList<Integer> list = new ArrayList<>();
        for(int i=0;i<arr2.length;i++){
            if(map.containsKey(arr2[i]) && map.get(arr2[i])>0){
                list.add(arr2[i]);
                //removing 1 value from HashMap
               map.put(arr2[i], map.get(arr2[i])-1);
            }
        }
        int arr[] = new int[list.size()];
        for(int i =0;i<list.size();i++){
            arr[i] = list.get(i);
        }
        return arr;
        
    }
}