Merge Sort in java

Here we implement merge sort in java.

• Divide and conquer algorithm
• Recursive algorithm
• Two phases: Splitting and Merging
• Not an in-place algorithm
• O(nlogn) time complexity
• Stable algorithm

public class MergeSort {
   public static void main(String[] args) {
       int[] arr = {9,8,7,6};
       mergeSort(arr, 0, arr.length);
       System.out.println("------------------------------------------------------");
       System.out.print("Sorted array: ");
       for (int i=0; i< arr.length; i++) {
           System.out.print(arr[i] + " ");
       }
   }
   public static void mergeSort(int[] inputArray, int start, int end) {
       System.out.println("start = "+start+ " : end = "+end);
       if (end - start < 2) {
           return;
       }
       int mid = (start + end) /2;
       mergeSort(inputArray, start, mid);
       mergeSort(inputArray, mid, end);
       merge(inputArray, start, mid, end);
   }
   public static void merge(int[] inputArray, int start, int mid, int end) {
       System.out.println("merge:---------------> "+"start = "+start + " | mid = "+mid + " | end = "+end);
       if (inputArray[mid-1] < inputArray[mid]) {
           return;
       }
       int[] tempArr = new int[end-start];
       int i = start;
       int j = mid;
       int currentIndex = 0;
       while(i < mid && j < end) {
           if (inputArray[i] > inputArray[j]) {
               tempArr[currentIndex] = inputArray[j];
               j++;
           } else {
               tempArr[currentIndex] = inputArray[i];
               i++;
           }
           currentIndex++;
       }
       while (i < mid) {
           tempArr[currentIndex] = inputArray[i];
           currentIndex++;
           i++;
       }
       while (j < end) {
           tempArr[currentIndex] = inputArray[j];
           currentIndex++;
           j++;
       }
       int index = 0;
       for (int k=start; k< end; k++) {
           inputArray[k] = tempArr[index];
           index++;
       }
   }
}

Console output

    start = 0 : end = 4
    start = 0 : end = 2
    start = 0 : end = 1
    start = 1 : end = 2
    merge:---------------> start = 0 | mid = 1 | end = 2
    start = 2 : end = 4
    start = 2 : end = 3
    start = 3 : end = 4
    merge:---------------> start = 2 | mid = 3 | end = 4
    merge:---------------> start = 0 | mid = 2 | end = 4
    ------------------------------------------------------
    Sorted array: 6 7 8 9 
    Process finished with exit code 0