RFR: 8341735: Rewrite the build/AbsPathsInImage.java test to not load the entire file at once [v6]

[Daniel Hu]

On Tue, 14 Oct 2025 21:53:41 GMT, Daniel Hu <duke at openjdk.org> wrote:

>> These changes should prevent entire binary files from being loaded into memory for build/AbsPathsInImage.java test. I chose a default buffer size of 8KB since BufferedInputStream uses that, but open to alternative solutions. GHA passes and test passes on linux x64.
>
> Daniel Hu has updated the pull request incrementally with two additional commits since the last revision:
> 
>  - fix incorrect use of inputstream
>  - remove extraneous variables/imports

test/jdk/build/AbsPathsInImage.java line 313:

> 311:         }
> 312:         System.out.println();
> 313:     }

I wanted to keep the debug output as close to the original as possible. But the original method backtracks to a non-ascii value, and that gets really complicated with the new buffered solution as probably a 2nd buffer would need to be kept while not being able to guarantee a static space complexity requirement (as who knows how much bytes are between each pair of ascii bytes). Moreover, when the test passes, a 2nd buffer kept for debug output isn't even used, meaning a pointless space penalty for the common case.

Instead, I added a secondary function that simply re-scans the file when the test fails. That does mean the test might take twice as long during failure (and all the associated additional space requirements), but I think that's an acceptable tradeoff, as vast majority of runs won't receive this penalty.

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PR Review Comment: https://git.openjdk.org/jdk/pull/26030#discussion_r2452876592