Java Quicksort Help

Question

I am trying to implement a quick sort in java. However, I am experiencing odd behavior. My algorithm works for 70 items or less but anything above that makes the entire java app freeze. is this is a limit to function calls or the amount of memory I'm using?

I don't normally use quicksort so my implementation might be a little off but I think in general the logic is correct:

int data[];

public void QuickSort(int start, int end)
{
            if(start == end || end < start || end > data.length)
            {
                return;
            }

            //find the pivot
            int pivotPos = (int)(start + (end - start) / 2);
            int temp;

            //switch the pivot to the end
            temp = data[pivotPos];
            data[pivotPos] = data[end];
            data[end] = temp;

            int LowerPoint = start;
            int HigherPoint = end - 1;

            //loop through and move low values down
            //and high values up
            while(LowerPoint != HigherPoint)
            {
                while(data[LowerPoint] < data[end] && LowerPoint < HigherPoint)
                {
                    LowerPoint++;
                }

                while(data[HigherPoint] > data[end]  && LowerPoint < HigherPoint)
                {
                    HigherPoint--;
                }

                if(LowerPoint != HigherPoint)
                {
                    temp = data[HigherPoint];
                    data[HigherPoint] = data[LowerPoint];
                    data[LowerPoint] = temp;
                }
            }

            //one last check to make sure we don't swap the pivot with a lower value
            //if this value is lower than increment our pointers up so we guarentee
            //the swap with a higher value
            if(data[LowerPoint] < data[end])
            {
                LowerPoint++;
                HigherPoint++;
            }

            //place the pivot back to the middle of the list
            //by swapping it with the higher point
            temp = data[HigherPoint];
            data[HigherPoint] = data[end];
            data[end] = temp;

            this.QuickSort(0, LowerPoint - 1);
            this.QuickSort(HigherPoint + 1, end);

        }

Any help is greatly appreciated.

Answer 1

Take a look at the follow 2 lines carefully:

    this.QuickSort(0, LowerPoint - 1);
    this.QuickSort(HigherPoint + 1, end);

There's something not quite right about them.