On Mon, 20 Feb 2023 17:03:33 GMT, Peter Levart <plev...@openjdk.org> wrote:
>> We don't fear calling the factory twice for benign races, as the distinct >> constructor factory instances are behaviorally the same. >> >> The true issue lies in the double getfield operations: Java memory model >> doesn't require the second read to happen-after a write reflected in the >> first read, so return this.genericInfo may return null while >> this.genericInfo == null evaluates to false, in case genericInfo is >> initialized lazily by another thread. See >> https://bugs.openjdk.org/browse/JDK-8261404 > > Hi @liach, > > I think @dholmes-ora is worried about the fields in the object being returned > by the getGenericInfo() method and similar. In above case this means fields > in class ConstructorRepository. > I checked it and the entire hierarchy based on > sun.reflect.generics.repository.AbstractRepository with subclasses including > ConstructorRepository is modeled such that all fields are either: > - volatile and lazily initialized; or > - final and initialized in constructor > > Such objects may be published via data race and still be seen consistent on > the accepting side. Thanks @plevart that was exactly my concern but I didn't have time to check whether the returned object could be safely published regardless of any race condition. Is it specified that way, or just a fortuitous occurrence? I would also be concerned about the guarantee of idempotency from the factory method - I hope its requirements in that area are clearly documented. ------------- PR: https://git.openjdk.org/jdk/pull/12643
