Write a Java program modifying the standard Merge Sort algorithm to perform the merging of the two subarrays in-place, without using any additional memory for creating temporary arrays. The goal is to reduce the overall space complexity of the algorithm.

public class MergeSort {
    public static void sort(int[] arr) {
        sort(arr, 0, arr.length-1);
    }

    private static void sort(int[] arr, int low, int high) {
        if (high <= low) {
            return;
        }

        int mid = low + (high - low) / 2;
        sort(arr, low, mid);
        sort(arr, mid+1, high);
        merge(arr, low, mid, high);
    }

    private static void merge(int[] arr, int low, int mid, int high) {
        int i = low;
        int j = mid+1;

        while (i <= mid && j <= high) {
            if (arr[i] <= arr[j]) {
                i++;
            } else {
                int temp = arr[j];
                System.arraycopy(arr, i, arr, i+1, j-i);
                arr[i] = temp;
                i++;
                mid++;
                j++;
            }