Radix Sort Java Implementation

int main()
{
    int arr[] = {53,3,542,748,14,214};

}
void radixSort(int[] arr)
{    
        //Buckets (one bucket = one array)
        int[][] bucket = new int[10][arr.length]
        //In order to record the # of vals stored in each bucket each time,we use an array to hold the these 10 #. 
        int[] bucketElementCounts = new int[10];

        //Iterations (LSN)
        for(int i=0,n=1;i<N;i++,n*=10)
        {
            for(int j = 0; j < arr.length; j++)
            {
                int digitOfElement = arr[j]/n%10;

                //Put them into corrsponding bucket
                bucket[digitOfElement][bucketElementCounts[digitOfElement]] 
                =arr[j];
                bucketElementCounts[digitOfElement]++; 
            }
            //Traverse every bucket.Put back data into sequence.
            int index = 0;
            for(int k= 0; k < 10; k++  )
            {
                if(bucketElementCounts[k] != 0)
                {
                    for(int l=0; l<bucketElementCounts[k];l++)
                    {
                        arr[index] = bucket[k][l];
                        index++;
                    }
                }
                //important, bucketElementCounts[k] = 0
                bucketElementCounts[k] = 0;
            }
            PRINT: (arr)
        }
}