On Sun, 18 Oct 2026 05:27:40 GMT, Srikanth Palutla <[email protected]> wrote:
>> Problem >> new PriorityQueue<>(List.of(new Object())) succeeds today when it should >> throw ClassCastException. initFromCollection relies on heapify() to surface >> incomparable elements, but heapify performs no comparisons on a singleton, >> so the lone element is never validated. Collections with two or more >> non-Comparable elements already throw. >> >> Fix >> In initFromCollection, when the collection holds exactly one element and no >> comparator is in play, self-compare the element before heapifying. This >> mirrors what TreeMap does for its first key (see JDK-5045147). Behavior with >> an explicit comparator is unchanged: non-Comparable elements are still >> accepted when a comparator is provided. >> >> Testing >> Added a copyConstructorSingleton regression test to AddNonComparable >> covering PriorityQueue(Collection) and PriorityQueue(Collection, Comparator) >> with a null comparator, plus the positive cases (Comparable singleton, >> explicit comparator). Verified the new test passes against the patched class >> and the existing queues() test still passes. >> >> >> Please let me know for further questions >> >> >> --------- >> - [x] I confirm that I make this contribution in accordance with the >> [OpenJDK Interim AI Policy](https://openjdk.org/legal/ai). > > Friendly ping — this has been awaiting review since September. Quick recap: > PriorityQueue.initFromCollection never validates a single-element collection > (heapify performs no comparisons on a singleton), so new > PriorityQueue<>(List.of(new Object())) succeeds where it should throw > ClassCastException. The fix self-compares the lone element when no comparator > is set, mirroring TreeMap's first-key check (JDK-5045147). All automated > checks are green; it just needs a Reviewer. > > @viktorklang-ora @liach — you both reviewed the recent PriorityQueue > constructor work in #31452; if either of you has a few minutes, a review here > would be much appreciated. > Hello @sripal2013, reading through some of the comments in this PR, to me, it > sounds like they may have been generated using LLM. Can you confirm whether > or not that's the case? The OpenJDK LLM policy https://openjdk.org/legal/ai > applies even for PR comments. Hello @jaikiran thanks for pointing it out . The analysis behind the replies is by me. However, I am not a native English speaker, to explain the changes better, I had to use AI. I was not aware of the comments policy. I had updated the comments. ------------- PR Comment: https://git.openjdk.org/jdk/pull/32966#issuecomment-6281086397
