MergeSort written in java that sorts specified range into ascending order.

Lets assume that A[4] = {4,3,2,1}.
My addition allows you to specify which range you want to be sorted.

As an example the output of mergeSort(A,2,3) is {4,3,1,2}. As you can see the specified range was sorted (2-3), you can of course sort the whole array by changing the parameters of the function.