MergeSort implemented in Java

private static void merge(int[] source, int[] buffer, int startingIndex, int count) {
    int lowerIndex = startingIndex;
    int lowerBound = startingIndex + count / 2;
    int upperIndex = lowerBound;
    int upperBound = startingIndex + count;

    for(int i = startingIndex ; i < upperBound ; i++){
        if(upperIndex >= upperBound ){
          System.arraycopy(source, lowerIndex , buffer, i, i - startingIndex );
          return;
        }
        if(lowerIndex >= lowerBound ){
          System.arraycopy(source, upperIndex , buffer, i, i - startingIndex );
          return;
        }
        buffer[i] = source[lowerIndex] < source[upperIndex] ? source[lowerIndex++] : source[upperIndex++]
    }
}

Merge Sort recurrently   implemented by  Divide and conquer Algorithm.