stack main()

public static void main(String[] args) {
    /* Stack demo */
    Stack<Integer> stack = new Stack<>();

    stack.push(2);
    stack.push(8);
    stack.push(5);

    System.out.println("Stack demo: ");
    System.out.println("peek: " + stack.peek());
    System.out.println(stack.pop());
    System.out.println(stack.pop());
    System.out.println(stack.pop());

    stack.push(10);
    System.out.println("stack size: " + stack.size());
}