RFR: 8314236: Overflow in Collections.rotate

[Aleksey Shipilev]

On Mon, 14 Aug 2023 12:56:46 GMT, Nikita Sakharin <duke at openjdk.org> wrote:

> `Collections.rotate` method contains a bug. This method throws IndexOutOfBoundsException on arrays larger than $2^{30}$ elements. The way to reproduce:
> 
> final int size = (1 << 30) + 1;
> final List<Byte> list = new ArrayList<>(size);
> for (int i = 0; i < size; ++i)
>     list.add((byte) 0);
> Collections.rotate(list, size - 1);
> 
> Output:
> ```Exception in thread "main" java.lang.IndexOutOfBoundsException: Index -2147483648 out of bounds for length 1073741825```
> 
> In that case private method `Collections.rotate1` will be called. And the line:
> `i += distance;`
> will cause overflow. I fixed this method and wrote a test for it.
> 
> I've signed the Oracle Contributor Agreement, but I don't have permission to raise a bug in the JDK Bug System.
> 
> Kindly ask you to raise a bug.

Submitted: [JDK-8314236](https://bugs.openjdk.org/browse/JDK-8314236)

Please change the PR synopsis to: "8314236: Overflow in Collections.rotate".

Also go to https://github.com/nikita-sakharin/jdk/actions, and enable testing workflows.

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PR Comment: https://git.openjdk.org/jdk/pull/15270#issuecomment-1678006190