Unexepcted OutOfMemoryError from Arrays.deepToString

[Andrey Turbanov]

Created PR to remove AbstractStringBuilder.MAX_ARRAY_SIZE -
https://github.com/openjdk/jdk/pull/5878

BTW, I found one more place where Integer.MAX_VALUE is used as maximum
array length - java.util.concurrent.ScheduledThreadPoolExecutor.DelayedWorkQueue#grow
I think this method could be reworked to take advantage of
ArraysSupport.newLength method too.


Andrey Turbanov

сб, 9 окт. 2021 г. в 20:09, Pavel Rappo <pavel.rappo at oracle.com>:
>
>
>
> > On 9 Oct 2021, at 13:07, Pavel Rappo <pavel.rappo at oracle.com> wrote:
> >
> > <snip>
> >
> > Separately, java.lang.AbstractStringBuilder#MAX_ARRAY_SIZE seems unused; I wonder how that happened.
>
> I found what happened:
>
> $ git log -S "MAX_ARRAY_SIZE" -- src/java.base/share/classes/java/lang/AbstractStringBuilder.java
> commit 03642a01af7123298d6524a98c99a3934d35c11b
> Author: Jim Laskey <jlaskey at openjdk.org>
> Date:   Thu Jun 11 10:08:23 2020 -0300
>
>     8230744: Several classes throw OutOfMemoryError without message
>
>     Reviewed-by: psandoz, martin, bchristi, rriggs, smarks
>
> Looking at the corresponding review thread, https://mail.openjdk.java.net/pipermail/core-libs-dev/2020-June/066874.html, the question about "the local orphan" MAX_ARRAY_SIZE was raised by Martin and subsequently addressed by Jim. The problem is, there were two of these fields. The one in PriorityBlockingQueue was spotted and deleted, the one in AbstractStringBuilder was not.
>
> Andrey, regardless of the outcome of your main question (OOM from Arrays.deepToString), would be willing to publish a PR to delete that field in AbstractStringBuilder?
>
> -Pavel
>
> >
> > -Pavel
> >
> >> On 9 Oct 2021, at 11:38, Andrey Turbanov <turbanoff at gmail.com> wrote:
> >>
> >> Hello.
> >> I came across unexpected behaviour of Arrays.deepToString method.
> >> It throws OOM even on non-huge arrays.
> >> For example this code:
> >>
> >>   int size = Integer.MAX_VALUE / 19;
> >>   Integer[] integers = new Integer[size];
> >>   Arrays.fill(integers, 0);
> >>  System.out.println(Arrays.deepToString(integers));
> >>
> >> Fails with following stack trace:
> >>
> >> Exception in thread "main" java.lang.OutOfMemoryError: Requested array
> >> size exceeds VM limit
> >>   at java.base/java.lang.AbstractStringBuilder.<init>(AbstractStringBuilder.java:86)
> >>   at java.base/java.lang.StringBuilder.<init>(StringBuilder.java:112)
> >>   at java.base/java.util.Arrays.deepToString(Arrays.java:5160)
> >>
> >>
> >> I believe it should be able to handle such arrays and not throw OOM
> >>
> >>
> >> Andrey Turbanov
> >
>