RFR: 8244297: Provide utility for testing for memory leaks [v10]
Florian Kirmaier
fkirmaier at openjdk.java.net
Tue Oct 27 19:27:25 UTC 2020
On Mon, 26 Oct 2020 22:49:41 GMT, Kevin Rushforth <kcr at openjdk.org> wrote:
>> Florian Kirmaier has updated the pull request incrementally with one additional commit since the last revision:
>>
>> JDK-8244297
>> Added some more whitespaces based on review
>
> modules/javafx.base/src/test/java/test/util/memory/JMemoryBuddy.java line 150:
>
>> 148: public static boolean checkNotCollectable(WeakReference weakReference) {
>> 149: createGarbage();
>> 150: System.gc();
>
> I recommend calling `System.runFinalization();` here.
>
> Also, do you think there is value in checking in a loop? Or is that overkill? One drawback of checking in a loop for the negative case is that you end up going through the loop all the way to the end in the expected case where a reference is not collectable, so it might be best to leave it as a single check as you have done.
I've added runFinalization followed with another System.gc (otherwise it wouldn't make any difference)
I'm quite sure it's avoiding an error in the library, but I don't have a unit-test for it yet.
It's a tradeoff between speed and reliability. The library tries to avoid false-negative test results at all costs.
false-positive results are tolerated for speed if they are "sufficiently reliable".
The Library has tests for assertNotCollectable, which are executed with every commit for different JVM's, and I don't remember any false-positive results (which would be visible as a negative test result, because the unit-test checks for failing tests). For that reason, we can assume they are "sufficiently reliable" despite the theoretical problem.
> modules/javafx.base/src/test/java/test/util/memory/JMemoryBuddy.java line 216:
>
>> 214: }
>> 215:
>> 216:
>
> Minor: there are extra blank lines here.
done
-------------
PR: https://git.openjdk.java.net/jfx/pull/204
More information about the openjfx-dev
mailing list