Sorting speeds

I was just wondering how the Arrays.sort() method is so fast. I created my own algorithm and ran it against quicksort and I was happy with the results, but then to make sure I was actually sorting the method correctly I used Arrays.sort() and Arrays.equals() and it finished too fast. My algorithm works...but the Arrays.sort() method sorted 30,000 ints in 20 milliseconds which pissed me off because My sort took like 7 seconds(i have an old computer). So, does anybody now why it is so much faster than both my sort and quicksort? and what sort does it use?

[566 byte] By [mythicwolf88a] at [2007-10-1 8:35:50]