Hashmaps:Longest subset zero sum

import java.util.*;

/*
	- You are given an integer array containing positive and negative numbers.
	- Your task is to find out the length of the longest continuous subset of this array whose elements add upto zero.

*/

public class solution 
{
    public static int lengthOfLongestSubsetWithZeroSum(ArrayList<Integer> arr) 
    {
        if(arr.size()==0)
            return 0;
        HashMap<Integer,Integer> h=new HashMap<>();
        int sum=0;
        int maxlength=0;
        int maxlength1=0;
        for(int i=0;i<arr.size();i++)
        {
            sum=sum+arr.get(i);
            if(h.containsKey(sum)){
                int k=h.get(sum);
                int l=i-k;
                maxlength1=l;}
             // if(!h.containsKey(sum))
            else
            h.put(sum,i);
            if(sum==0)
            {
                maxlength1=i+1;
            }
           
            if(maxlength1>maxlength)
                maxlength=maxlength1;
        }
return maxlength;
    }
}