class Solution {
    public String restoreString(String s, int[] indices) {
        char a[]=s.toCharArray();
        char arr[]=new char[s.length()];

        if(s.length()==indices.length)
        {
            for(int i=0;i<s.length();i++)
            {

               arr[indices[i]]=s.charAt(i); 
            }
        }
        return new String(arr);
        
        
    }
}

In the above problem, Why we are using new String method instead of toString method

I tried toString method , and I got error on that code. I want to clarify the difference between toString() and new String();