List class's toArray in Java- Why can't I convert a list of “Integer” to an “Integer” array?

Question

I defined List stack = new ArrayList();

When I\'m trying to convert it to an array in the following way:

Answer 1

Because of type erasure, the ArrayList does not know its generic type at runtime, so it can only give you the most general Object[]. You need to use the other toArray method which allows you to specify the type of the array that you want.

Integer[] array= stack.toArray(new Integer[stack.size()]);