Hi Piotr, In Java 9 we moved some documentation from Collectors.sort(List ) to List.sort, then back ported it. For more details see https://bugs.openjdk.java.net/browse/JDK-8030848 <https://bugs.openjdk.java.net/browse/JDK-8030848>
On List.sort: * @implNote * This implementation is a stable, adaptive, iterative mergesort that * requires far fewer than n lg(n) comparisons when the input array is * partially sorted, while offering the performance of a traditional * mergesort when the input array is randomly ordered. If the input array * is nearly sorted, the implementation requires approximately n * comparisons. Temporary storage requirements vary from a small constant * for nearly sorted input arrays to n/2 object references for randomly * ordered input arrays. Overall specification has not changed with regards to stable sorting. > On 16 Nov 2017, at 04:49, Piotr Findeisen <piotr.findei...@gmail.com> wrote: > > Hi, > > I just realised the Collections.sort(List) method ceased to be stable as of > Java 8 (sort of). > Do you have a specific bug or are you unsure with regards to the specification? Paul. > Although the method's documentation still promises stable sort, the > implementation delegates to List.sort(Comparator) and that interface method > bears no constraint that an implementation must sort stable. > > Is "stable" missing from List.sort's documentation? > Or, instead, should it be now no longer promised by Collections.sort? (oh, > no!) > Or, what am i missing? > > Best regards, > Piotr
