How to convert List to int[] in Java? [duplicate]

Answer 1

int[] toIntArray(List list)  {
    int[] ret = new int[list.size()];
    int i = 0;
    for (Integer e : list)  
        ret[i++] = e;
    return ret;
}

Slight change to your code to avoid expensive list indexing (since a List is not necessarily an ArrayList, but could be a linked list, for which random access is expensive)