Get Duplicates

import java.io.*;
import java.util.*;
class MyCode {


   /**
    *  Get Duplicates
    *
    *  Given an array of values, return only the values that have duplicates in the
    *  array
    *
    *  Parameters
    *  Input: arr {Array}
    *  Output: {ArrayList}
    *
    *  Constraints
    *  Time: O(N)
    *  Space: O(N)
    *
    *  Examples
    *  [1, 2, 4, 2] --> [2]
    *  [3, 2, 3, 2, 3, 3, 4] --> [3, 2]
    *  [1, 2, 3, 4] --> []
    */
    public static void main (String[] args) {
    int[] arr = new int[]{1, 2, 3, 4};
  ArrayList<Integer> l= new ArrayList<Integer>();
  l = getDuplicates(arr);

  }

   public static ArrayList<Integer> getDuplicates(int[] arr) {
      HashMap<Integer, Integer> map = new HashMap<Integer, Integer>();
      ArrayList<Integer> list = new ArrayList<Integer>();
      int count= 0;
      for(int i = 0; i<arr.length; i++){
        if(map.containsKey(arr[i])){
            count = map.get(arr[i]);
            map.put(arr[i],++count);
        }else{
            map.put(arr[i], 1);
        }
      }
      for(Map.Entry<Integer,Integer> entry: map.entrySet()){
          if(entry.getValue() > 1){
            list.add(entry.getKey());
          }
      }
      System.out.println(list);
      return list;
    }
}