I need help in returning Yes.

package mergeSort;

public class MergeSortTest {

private static void randomIntArray(Integer arr[], int min, int max) {

int mn = Math.min(min, max);

int mx = Math.max(min, max) + 1;

for(int i = 0; i < arr.length; i++) {

int value = (int)(Math.random() * (mx - mn)) + mn;

arr[i] = Integer.valueOf(value);

}

}

private static void randomStringArray(String arr[], int min, int max) {

if(min < 0) {

throw new IllegalArgumentException("Min for randomStringArray must be >= 0");

}

int mn = Math.min(min, max);

int mx = Math.max(min, max) + 1;

char alphabet[] = "abcdefghijklmnopqrstuvwxyz".toCharArray();

for(int i = 0; i < arr.length; i++) {

String s = "";

int rLen = (int)(Math.random() * (mx - mn)) + mn;

for(int j = 0; j < rLen; j++) {

int rCharIdx = (int)(Math.random() * alphabet.length);

s += alphabet[rCharIdx];

}

arr[i] = s;

}

}

private static boolean isSorted(Object arr[]) {

for(int i = 0; i < arr.length - 1; i++) {

if(((Comparable) arr[i]).compareTo(arr[i+1]) > 0) {

return false;

}

}

return true;

}

public static void main(String args[]) {

Integer iArr[] = new Integer[1000];

randomIntArray(iArr, 0, 100);

MergeSort.sort(iArr);

System.out.println("MERGE SORT INTEGER ARRAY IS SORTED? " + (isSorted(iArr) ? "YES" : "NO"));

String sArr[] = new String[1000];

randomStringArray(sArr, 10, 20);

MergeSort.sort(sArr);

System.out.println("MERGE SORT STRING ARRAY IS SORTED? " + (isSorted(iArr) ? "YES" : "NO"));

}

}

package mergeSort;

public class MergeSort {

public static void sort(Object arr[]) {}

private static void mergeSort(Object arr[], Object tempArray[], int first, int last) {

if(first < last) {

int mid = first + (last - first) / 2;

mergeSort(arr, tempArray, first, mid);

mergeSort(arr, tempArray, mid + 1, last);

merge(arr, tempArray, first, mid, last);

}}

private static void merge(Object arr[], Object tempArray[], int first, int mid, int last) {

int beginHalf1 = first;

int endHalf1 = mid;

int beginHalf2 = mid + 1;

int endHalf2 = last;

int index = 0;

while(beginHalf1 <= endHalf1 && beginHalf2 <= endHalf2);

int res = ((Comparable) arr[beginHalf1]).compareTo(arr[beginHalf2]);

if(res <= 0) {

} else {

}

while(beginHalf1 <= endHalf1) {

tempArray[index] = arr[beginHalf1];

index ++;

beginHalf1++;

}

while(beginHalf2 <= endHalf2) {

tempArray[index] = arr[beginHalf2];

index++;

beginHalf2++;

for(int i = 0, j = first; i <= (last - first); i++, j++) {

arr[j] = tempArray[i];

}

}

}

}