AOT Map changes during production run

[Vladimir Kozlov]

On 10/9/25 8:16 AM, Vladimir Kozlov wrote:
> Hi María,
> 
> Please provide command lines you use in your experiments.
> 
>  >         And then I did a production run using the generated cache, which
>  >         replaced the `aot.map` with a new one that is much smaller:
> 
> We don't support incremental update of AOT cache file. What do you mean 
> by "replaced the `aot.map`" ?

Sorry, I confused aot.map with aot.cache.

I assume aot.map is log file produced from AOT cache logs output.

Still it would be interesting to see your commands.

Vladimir K

> 
> Thanks,
> Vladimir K
> 
> On 10/9/25 12:25 AM, María Arias de Reyna Dominguez wrote:
>> Hi Ashutosh,
>>
>> Training run:
>> $ grep '@@ Class ' aot.map | wc -l
>> 10884
>>
>> Production run:
>> $ grep '@@ Class ' aot.map | wc -l
>> 3431
>>
>> And the sizes of the map file are different:
>> $ du -sh aot.map*
>> 331M aot.map
>> 391M aot.map.0
>> 394M aot.map.1
>>
>> The aot.map is the production run. The file aot.map.1 is the training 
>> run.
>>
>> The aot.map.0 is for app.aot.config (app.aot is how I call my aot cache):
>> $ cat aot.map.0 | head
>> AOT cache map for app.aot.config
>> [header             0x0000000000000000 - 0x00000000000003d8       984 
>> bytes]
>> $ grep '@@ Class ' aot.map.0 | wc -l
>> 10606
>>
>> I'm using a locally build version of Java, that's true:
>> $ java --version
>> openjdk 26-internal 2026-03-17
>> OpenJDK Runtime Environment (build 26-internal-adhoc.delawen.jdk)
>> OpenJDK 64-Bit Server VM (build 26-internal-adhoc.delawen.jdk, mixed 
>> mode, sharing)
>>
>> Build from:
>> $ git log | head
>> commit 4b4d0cd35a32448e4b056109c502af2765766432
>> Author: Johny Jose <johny.jose at oracle.com <mailto:johny.jose at oracle.com>>
>> Date:   Tue Oct 7 13:13:42 2025 +0000
>>
>>      8365398: TEST_BUG: java/rmi/transport/checkLeaseInfoLeak/ 
>> CheckLeaseLeak.java failing intermittently
>>
>>      Reviewed-by: msheppar, smarks, jpai
>>
>> I'm confused :)
>>
>> On Wed, Oct 8, 2025 at 6:31 PM Ashutosh Mehra <asmehra at redhat.com 
>> <mailto:asmehra at redhat.com>> wrote:
>>
>>     Hi Maria,
>>     This is strange. I tried the same using the JavacBench app and
>>     didn't see this discrepancy in the map file generated by the
>>     assembly phase and the production run.
>>     You may have already checked it but just to confirm if run "grep '@@
>>     Class ' t.log | wc -l" on the map file, do you see the same 
>> difference?
>>
>>     Thanks,
>>     - Ashutosh Mehra
>>
>>
>>     On Wed, Oct 8, 2025 at 4:36 AM María Arias de Reyna Dominguez
>>     <mariasde at redhat.com <mailto:mariasde at redhat.com>> wrote:
>>
>>         Hi!
>>
>>         I have a question.  I did a training run and generated what
>>         looks like a valid cache.
>>
>>         Summary of the number of elements (for certain types of
>>         elements) the map contains:
>>         ```
>>         Classes in AOT Cache: 10.885
>>         Methods in AOT Cache: 121.393
>>            -> ConstMethods: 121.293
>>            -> MethodCounters: 6.530
>>            -> MethodData: 4.127
>>         ConstantPool: 10.197
>>            -> ConstantPoolCache: 10.197
>>         ```
>>
>>         And then I did a production run using the generated cache, which
>>         replaced the `aot.map` with a new one that is much smaller:
>>
>>         ```
>>         Classes in AOT Cache: 3.431
>>         Methods in AOT Cache: 38.359
>>            -> ConstMethods: 38.359
>>            -> MethodCounters: 0
>>            -> MethodData: 0
>>         ConstantPool: 3.067
>>            -> ConstantPoolCache: 3.067
>>         ```
>>
>>         As you can see, there are a lot of missing elements!
>>
>>         If I check the md5sum of the actual cache file before and after
>>         the production run, it stays the same. It is the AOT Cache Map
>>         which changes. Is that... supposed to happen?
>>
>>         Maybe it is a bug related to https://bugs.openjdk.org/browse/
>>         JDK-8362566 <https://bugs.openjdk.org/browse/JDK-8362566> ?
>>
>>         Both map files start with `AOT cache map for app.aot`, it is not
>>         the map file for the `app.aot.config` that appears during the
>>         training run.
>>
>>         Both the training and the run were the same: just spin up an
>>         Infinispan server and shut it down after a few seconds. But I
>>         guess that's irrelevant because the aot cache file is exactly
>>         the same.
>>
>>         I could stop generating the aot map file on the production run
>>         because there is no need for it, but I forgot to remove it...
>>         and then this happened.
>>
>>         Kind regards,
>>         María Arias de Reyna Domínguez
>>         Senior Software Engineer
>>         She / Her / Hers
>>         ariasdereyna at redhat.com <mailto:ariasdereyna at redhat.com>
>>
>