The following line

        Collections.emptyList().sort((Comparator)null);

Leads to

Exception in thread "main" java.lang.NullPointerException
at java.util.Objects.requireNonNull(Objects.java:203)
at java.util.Collections$EmptyList.sort(Collections.java:4523)

While the spec on j.u.List.sort(Comparator) says:
"A null value indicates that the elements' natural ordering should be used"


In the implementation this looks like a result of a copy-paste mistake.

The following JCK test will fail:

api/java_util/Collections/empty/EmptyListSort.html#EmptyListSort[elementSettingNotSupported_naturalSorting]