Convert nested list to 2d array

Question

I\'m trying to convert a nested list into a 2d array.

List> list = new ArrayList<>();

list.add(Arrays.asList(\"a\", \"b\", \"         


        

Answer 1

This is the best and most efficient way to convert 2d list to 2d array;

List>  list2d = new ArrayList<>();
Integer[][] array2d;

array2d = list2d.stream().map(x->x.toArray(new Integer[x.size()])).toArray(Integer[][]::new);