It was about time I made myself a blog. I will write in english to be able to reach out to as many as possble. The first thing that came to my mind to publish, was a quicksort implementation in java I recently wrote.
Quicksort is pretty fast. And runs in O(n lg n) on average.

I wrote it for educational purposes. If you need to sort something in java, you should probably use Arrays.sort, which can sort objects that implements the Comparable interface.

public static void quicksort(int[] a, int low, int high) {
    if(low < high) {
        int pivot = partition(a, low, high);
        quicksort(a, low, pivot - 1);
        quicksort(a, pivot + 1, high);
    }
}

// randomized partition
public static int partition(int[] a, int low, int high) {
    int i = low;

    int pivotIndex = (int) Math.random() * (high-low);
    int tmp = a[low + pivotIndex];
    a[low + pivotIndex] = a[high];
    a[high] = tmp;
    int pivot = a[high];

    for(int j = low; j < high; j++) {
        if(a[j] <= pivot) {
            tmp = a[i];
            a[i] = a[j];
            a[j] = tmp;
            i += 1;
        }
    }
    tmp = a[i];
    a[i] = a[high];
    a[high] = tmp;
    return i;
}