On Fri, 19 Dec 2025 07:41:09 GMT, Jaikiran Pai <[email protected]> wrote:
> Can I please get a review of this test-only change which addresses > intermittent failures in > `java/rmi/server/Unreferenced/leaseCheckInterval/LeaseCheckInterval.java`? > > The `@summary` in that test's test definition about what this test does: > >> @summary When the "java.rmi.dgc.leaseValue" system property is set to a >> value much lower than its default (10 minutes), then the server-side >> user-visible detection of DGC lease expiration-- in the form of >> Unreferenced.unreferenced() invocations and possibly even local garbage >> collection (including weak reference notification, finalization, etc.)-- >> may be delayed longer than expected. While this is not a spec violation >> (because there are no timeliness guarantees for any of these garbage >> collection-related events), the user might expect that an unreferenced() >> invocation for an object whose last client has terminated abnormally >> should occur on relatively the same time order as the lease value >> granted. > > In its current form, the test uses a lease expiry of 10 seconds, launches a > trivial `java` application which looks up the bound object from the registry > and then terminates itself. After launching that trivial java application, > the test then waits for 20 seconds, expecting that the > `Unreferenced.unreferenced()` callback (upon lease expiry of 10 seconds) will > be called within those 20 seconds. This wait intermittently fails because the > `Unreferenced.unreferenced()` doesn't get called within those 20 seconds. > > Experiments show that the reason for these intermittent failures is due to > the `SelfTerminator` application which does the registry lookup (and which > involves connection establishment and communication over a socket) can > sometimes take several seconds (5 or more for example). That effectively > means that by the time this `SelfTerminator` starts its termination after the > lookup, it's already several seconds into the "wait()" in the test. > > The commit in this PR cleans up the test to more accurately track the > duration of how long it took between the lease expiry and the > `Unreferenced.unreferenced()` callback to be invoked. Additionally, just to > make the test more robust, the maximum expected duration has been increased > to 60 seconds instead of 20 seconds. Given the text in the test's summary, I > think this increase is still within the expectations of how long it takes for > the callback to be invoked after the client has exited abnormally. > > The test continues to pass with this change and a te... replacing the obj.lock.wait(TIMEOUT); with the do while loop is a good change as the Object.wait is susceptible to intermittent early return. jtreg takes care of a test timeout. BUT I think it possible to simply the main test logic a bit. The Object wait/notify could be replaced by a CountDownLatch. The remote unreferenced method counts down the latch and the main test thread awaits the count down of the latch (in place of the do while). Thus removing the synchronize logic. This eliminates the necessity for the assert assert and for a state variable unreferenced. lines 121 - 136 are a refactor extract method isWithinTimeLimits one could debate if the temporal checks are necessary, as they cannot be guaranteed. ------------- PR Comment: https://git.openjdk.org/jdk/pull/28919#issuecomment-3676932915
