MergeSort Implementation in Java

Question

import java.util.Arrays;

public class mergeSort{

    public static void main(String[] args) {

    int[] arr = {2, 4, 5, 7, 1, 2, 3, 6};
    int size = arr.length;
    int[] L, R;

    L = new int[size/2]; //setup both the left and right side arrays
    R = new int[size/2];

    int k, i = 0, j = 0;

    for(k = 0; k < size; k++){
        if (k < size/2){
            L[i] =  arr[k];
            i++; //iterate through the left side
        }
        else{
            R[j] =  arr[k];
            j++;// iterate through the right side
        }

    }

    i = 0;
    j = 0;

    for (k = 0; k < size; k++){
        if (i < L.length && j < R.length){
            if(L[i] < R[j]){
                arr[k] = L[i];
                i++;
            }
            else{
                arr[k] = R[j];
                j++;
            }
        }

    }


    printArray(arr);    
    }

    public static void printArray(int[] arrayToPrint) {
    for (int i = 0; i < arrayToPrint.length; i++) {
        System.out.print(arrayToPrint[i] + " ");
    }
    System.out.print("\n");
}




}

I am working on an implementation for merge sort. But for some reason I am not getting the correct results. The answer I get when I try to sort this array is this: "1 2 2 3 4 5 6 6". I don't understand where "7" goes. And if I remove an element from the array I get an ArrayIndexOutOfBoundsException.

With the array out of bounds exception, I dont understand where exactly I am going wrong. I increased the size of the array but it doesnt change the result. Am I looking at it with an incorrect approach?

Thanks!