Merge sort

import java.util.*;
class mergesort
{
     public static void main(String args[])
    {
        Scanner sc = new Scanner(System.in);
        System.out.println("Enter size");
        int n = sc.nextInt();
        int arr[] = new int[n];
        System.out.println("Enter array");

        for(int x=0; x<n; x++)
            arr[x] = sc.nextInt();

        System.out.println("\nGiven Array \n"+ Arrays.toString(arr));

        mergesort m = new mergesort();
        m.sort(arr, 0, arr.length - 1);

        System.out.println("\nSorted Array \n"+ Arrays.toString(arr));

    }

    void mergefun(int arr[], int start, int mid, int end)
    {
        int n1 = mid - start + 1;
        int n2 = end - mid;

        int L[] = new int[n1];
        int R[] = new int[n2];

        for (int i = 0; i < n1; ++i)
            L[i] = arr[start + i];
        for (int j = 0; j < n2; ++j)
            R[j] = arr[mid + 1 + j];
        int i = 0, j = 0;
        for(int x = start; x<=end; x++){
            if(i < n1 && j < n2){
                if (L[i] <= R[j]){
                    arr[x] = L[i];
                    i++;
                }
                else {
                    arr[x] = R[j];
                    j++;
                }
            }
            else{
                if(i < n1){
                    arr[x] = L[i];
                    i++;
                }

                if(j < n2){
                    arr[x] = R[j];
                    j++;
                }
            }
        }
    }

    void sort(int arr[], int l, int r)
    {
        if (l < r) {
            int m = (l + r) / 2;

            sort(arr, l, m);
            sort(arr, m + 1, r);
            mergefun(arr, l, m, r);
        }
    }
}