We should be careful with words here. I think that in this thread people use "deterministic" casually as a synonym for "defined". "Defined" means not only repeatable but also specific. What's more, people seem to want to be able to specify it. So, arguably a better way would be to refer to such an order as **user-defined**.
Back to Map.of. Even if a user could control the seed of the current implementation, the order would not be user-defined. It would be deterministic though. If the implementation of Map.of or the hash code of the objects a user stores there were to suddenly change, the order could change too. Be it Map.of or HashMap, there's no user-defined order. The only user-defined order one can currently get is by using LinkedHashMap. In the future though, we may get SequencedMap.of. On Fri, Sep 5, 2025 at 4:52 PM Ryan Ernst <r...@iernst.net> wrote: > > The iteration order is deterministic. The problem raised in that thread was > that the seed is hidden and uncontrollable. > > IMO if you want a Map that has order, use a LinkedHashMap (or the idea is > SequencedMap.of is also appealing). However, even if you don’t want to depend > on iteration order, sometimes there are bugs that unintentionally depend on > that order, so it would still be great to control the seed in order to have > reproducibility in tests. > > On Sep 5, 2025, at 08:23, Kevin Bourrillion <kevin.bourrill...@oracle.com> > wrote: > > > > Just as a corroborating data point, it’s banned at my previous company too, > and this is a big reason why. Deterministic iteration is a very good thing. > (Personal opinion: I’ve come to view non-deterministic iteration as a risky > optimization in general, that is usually not called for.) > > > > > > From: core-libs-dev <core-libs-dev-r...@openjdk.org> on behalf of Stephen > Colebourne <scolebou...@joda.org> > Date: Friday, September 5, 2025 at 12:13 AM > To: core-libs-dev <core-libs-dev@openjdk.org> > Subject: StableValue and non-deterministic iteration order > > > In summary, the current Map.of() is a bit of a hand grenade IMO, and > something I pretty much banned at my previous company. Which is a > problem given its key role in StableValue. > > Stephen
