@Test
public void testGetSize() {

    Assertions.assertEquals(0, ClassUtils.getSize(null));
    List<Integer> list = new ArrayList<>();
    list.add(1);
    Assertions.assertEquals(1, ClassUtils.getSize(list));
    Map map = new HashMap();
    map.put(1, 1);
    Assertions.assertEquals(1, ClassUtils.getSize(map));
    int[] array = new int[1];
    Assertions.assertEquals(1, ClassUtils.getSize(array));
    Assertions.assertEquals(-1, ClassUtils.getSize(new Object()));
}