Why does java.util.Arrays.sort(Object[]) use 2 kinds of sorting algorithms?

Question

I found that java.util.Arrays.sort(Object[]) use 2 kinds of sorting algorithms(in JDK 1.6).

pseudocode:

if(array.length<7)
   inserti         


        

Answer 1

It appears that they believe mergeSort(array) is slower for short arrays. Hopefully they actually tested that.