Merge Sort Implementation using Java

import java.io.BufferedReader;
import java.io.InputStreamReader;
 
public class MergeSort {
/*********************************************************************************
 The arrayUnsorted[] is where user inputs the unsorted elements
 arraySorted[]-array which will contain the elements of in sorted order
 temp[]-array which is used for temporary use
 length-indicates the number of elements in the array
 *********************************************************************************/
    int length,i;
    int arrayUnsorted[],arraySorted[],temp[];
    public static void main(String[] args) throws Exception{
       
        MergeSort ms=new MergeSort();
        ms.readArray();
        System.out.println("The Unsorted array is ");
        ms.displayArray(ms.arrayUnsorted);
        /*************************************************************************
         The array arrayUnsorted[] is copied to arraySorted[]
         mergeSort
         *************************************************************************/
        ms.copyArray(ms.arrayUnsorted, ms.arraySorted, 0, ms.length-1);
        ms.mergeSort(0, ms.length-1);
        System.out.println("The Sorted array is ");
        ms.displayArray(ms.arraySorted);

    }
    /*******************************************************************
     function readArray() reads the length of array & then reads all 
     elements to arrayUnsorted[]
     *******************************************************************/
    private void readArray() throws Exception{
        System.out.println("Enter the number of elements  in the array");
        length=readNo();
        arrayUnsorted=new int[length];
        arraySorted=new int[length];
        temp=new int[length];
        System.out.println("Enter the elements of array");
        for(i=0;i            arrayUnsorted[i]=readNo();   
        }
    }
    /*******************************************************************
     function readNo() reads an integer from keyboard & returns it
     *******************************************************************/
    private int readNo() throws Exception{
        String enteredElement;
        InputStreamReader isr=new InputStreamReader(System.in);
        BufferedReader br=new BufferedReader(isr);
        enteredElement=br.readLine();
        int no=Integer.parseInt(enteredElement);
        return no;
    }
    /**************************************************************************
     function displayArray() is used to display all the elements of the array,
     which  given as its input 
     **************************************************************************/
    private void displayArray(int[] arrayToDisplay ){
        int i;
        for(i=0;i                System.out.print(arrayToDisplay[i]);
                System.out.print(" ");
        }
        System.out.println();   
    }
    /*****************************************************************************
     function mergeSort() is where original divide and conquer approach happens.Here 
     the lower & upper limit of array are taken as input & the whole array is split 
     into two subarrays.Then these two subarrays are again divided until subarray 
     will have 1 element in it.Then sub arrays are merged in a sorted manner
     *****************************************************************************/
    private void mergeSort(int low,int high){
        if(low            int mid=(low+high)/2;
            mergeSort(low, mid);
            mergeSort(mid+1, high);
            merge(low,mid,high);           
        }               
    }
    /*****************************************************************************
     function merge() is used to merge two subarrays in a sorted manner.For temporary 
     storing results of sorted array, temp[] array is used.
     In this function the subarrays are individually sorted.The subarray elements are 
     compared with other & the elements of both array are stored to temporary array 
     in sorted manner.After sorting  the both arrays & then the sorted result is copied 
     from temp[] array to arraySorted[] 
     ******************************************************************************/
    private void merge(int low,int mid,int high){
        int i,j,k;
        i=j=low;
        k=mid+1;
        while(i<=mid&&k<=high){
            if(arraySorted[i]<=arraySorted[k]){
                temp[j]=arraySorted[i];
                i++;
            }
            else{
                temp[j]=arraySorted[k];
                k++;
               
            }
            j++;
        }
        while(i<=mid){
            temp[j]=arraySorted[i];
            j++;i++;
        }
        while(k<=high){
            temp[j]=arraySorted[k];
            k++;
            j++;
        }       
        copyArray(temp, arraySorted, low,high);       
    }   
    /****************************************************************************
      function copyArray() is used to copy existingArray[] to newArray with lower 
      & upper limits as existingArrayLow & existingArrayHigh 
     ***************************************************************************/
    private void copyArray(int existingArray[],int newArray[],int existingArrayLow,int existingArrayHigh){
        for(int i=existingArrayLow;i<=existingArrayHigh;i++){
            newArray[i]=existingArray[i];
        }       
    }
}