@Test
public void concatWithNewItemsAndNulls() {

  ArrayList<String> originalList = new ArrayList<>();
  originalList.add("hi");
  originalList.add("sup");
  List<String> result = CollectionUtil.concatList(originalList, "nice", null, "dog", null);
  assertThat(result)
      .containsExactly("hi", "sup", "nice", "dog");
}