Arrays.sort(new String[]{"aaa"}); 排序方法

    private static void mergeSort(Object[] src,

                  Object[] dest,

                  int low,

                  int high,

                  int off) {

    int length = high - low;



    // Insertion sort on smallest arrays

        if (length < INSERTIONSORT_THRESHOLD) {

            for (int i=low; i<high; i++)

                for (int j=i; j>low &&

             ((Comparable) dest[j-1]).compareTo(dest[j])>0; j--)

                    swap(dest, j, j-1);

            return;

        }



        // Recursively sort halves of dest into src

        int destLow  = low;

        int destHigh = high;

        low  += off;

        high += off;

        int mid = (low + high) >>> 1;

        mergeSort(dest, src, low, mid, -off);

        mergeSort(dest, src, mid, high, -off);



        // If list is already sorted, just copy from src to dest.  This is an

        // optimization that results in faster sorts for nearly ordered lists.

        if (((Comparable)src[mid-1]).compareTo(src[mid]) <= 0) {

            System.arraycopy(src, low, dest, destLow, length);

            return;

        }



        // Merge sorted halves (now in src) into dest

        for(int i = destLow, p = low, q = mid; i < destHigh; i++) {

            if (q >= high || p < mid && ((Comparable)src[p]).compareTo(src[q])<=0)

                dest[i] = src[p++];

            else

                dest[i] = src[q++];

        }

    }