RFR 8009736: Comparator API cleanup (original) (raw)

Paul Sandoz paul.sandoz at oracle.com
Wed Jun 12 16:36:59 UTC 2013

On Jun 12, 2013, at 5:54 PM, Henry Jen <henry.jen at oracle.com> wrote:

Comparator.reverseOrder + *

The returned comparator is serializable. Try to compare null with

+ * returned comparator will throw {@link NullPointerException}. + * Typo "Try to compare" (and to . Do you mean: The compare method of the returned comparator will throw a {@link NullPointerException} if a {@code null} value is passed as the second parameter. ? Perhaps add a "@See Collections#reverseOrder" and vice versa on that method. Similar issue for Comparator.naturalOrder but for null passed as the first parameter. Is "compare null using" better then "compare null with"?

It's more the tense of the sentence.

How about:

"The returned comparator is serializable and does not permit null arguments when comparing objects".

?

null passed as an argument will cause NPE on returned comparator, regardless position.

Doh!, of course :-) Comparable.compare(null) should also throw an NPE, just the stack trace will be slightly different.

Map.comparingByKey/Value(Comparator<? super K/V> cmp)

You don't mention "Note that a null key/value…" That's because null is handled by Comparator in this case, if the Comparator is null-friendly, it is fine. Perhaps I should make that clear.

Ah, yes, some clarification would be useful.

Paul.

More information about the core-libs-dev mailing list