MergeSort java

private static void mergeSort(int[] arr,int begin,int end){

        if(begin>=end)
            return;

        int middle=(begin+end)/2;
        mergeSort(arr,begin,middle); //first half
        mergeSort(arr,middle+1,end); // second half
        mergeHalves(arr,begin,middle,end);

    }


    private static void mergeHalves(int[] arr,int begin,int middle,int end){

        int firstContainerStorageLimit=middle-begin+1;
        int[] firstContainer=new int[firstContainerStorageLimit];

        int secondContainerStorageLimit=end-middle;
        int[] secondContainer=new int[secondContainerStorageLimit];

        //Copy data from original array to first container
        for(int i=0;i<firstContainerStorageLimit;i++)
            firstContainer[i]=arr[begin+i];

        //Copy data from original to second container
        for(int i=0;i<secondContainerStorageLimit;i++){
            secondContainer[i]=arr[middle+1+i];
        }

        int sortedContainerIndex=begin;

        int i=0,j=0;

        while(i<firstContainerStorageLimit && j<secondContainerStorageLimit){

            if(firstContainer[i] <= secondContainer[j]){
               arr[sortedContainerIndex]=firstContainer[i];
                i++;
            }
            else{
                arr[sortedContainerIndex]=secondContainer[j];
                j++;
            }

            sortedContainerIndex++;
        }

        while(i<firstContainerStorageLimit)
        {
            arr[sortedContainerIndex++]=firstContainer[i];
            i++;
        }

        while(j<secondContainerStorageLimit){
            arr[sortedContainerIndex++]=secondContainer[j];
            j++;
        }


    }