public boolean add(final Integer element)
    {
        return addInt(null == element ? nullValue : element);
    }
@Test
    void shouldCreateIntegerArray()
    {
        final int count = 20;
        final Integer[] expected = new Integer[count];
        for (int i = 0; i < count; i++)
        {
            list.add(i);
            expected[i] = i;
        }

        final Integer[] integers = list.toArray(new Integer[0]);
        assertEquals(expected.getClass(), integers.getClass());
        assertArrayEquals(expected, integers);
    }