# cache: /home/claude/spring-boot-demo/aot-cache/work/refresh.aot, trained on JDK 25.0.4.1, extracted layout, default GC (G1), 2 CPUs

== control: the same JVM, the same jar, the same path
   result:  started, ready after 1987 ms   (Started AotCacheApplication in 1.538 seconds)
   log:     (nothing at warning or error level)

== the application jar was rebuilt after a one-line code change, default AOTMode=auto
   result:  started, ready after 4124 ms   (Started AotCacheApplication in 3.453 seconds)
   log:    [warning][aot] This file is not the one used while building the AOT cache: 'app.jar', timestamp has changed, size has changed
   log:    [error  ][aot] An error has occurred while processing the AOT cache. Run with -Xlog:aot for details.
   log:    [error  ][aot] shared class paths mismatch (hint: enable -Xlog:class+path=info to diagnose the failure)
   log:    [error  ][aot] Unable to map shared spaces

== the same, with -XX:AOTMode=on
   result:  did not start (exit code 1)
   log:    [warning][aot] This file is not the one used while building the AOT cache: 'app.jar', timestamp has changed, size has changed
   log:    [error  ][aot] shared class paths mismatch (hint: enable -Xlog:class+path=info to diagnose the failure)
   log:    [error  ][aot] An error has occurred while processing the AOT cache. Run with -Xlog:aot for details.
   log:    [error  ][aot] unrecoverable error

== a dependency jar has a different modification time (same bytes)
   result:  started, ready after 3865 ms   (Started AotCacheApplication in 3.201 seconds)
   log:    [warning][aot] This file is not the one used while building the AOT cache: 'lib/spring-core-7.0.9.jar', timestamp has changed
   log:    [error  ][aot] An error has occurred while processing the AOT cache. Run with -Xlog:aot for details.
   log:    [error  ][aot] shared class paths mismatch (hint: enable -Xlog:class+path=info to diagnose the failure)
   log:    [error  ][aot] Unable to map shared spaces

== the same files copied with plain cp (bytes and path layout identical, timestamps new)
   result:  started, ready after 4013 ms   (Started AotCacheApplication in 3.361 seconds)
   log:    [warning][aot] This file is not the one used while building the AOT cache: 'app.jar', timestamp has changed
   log:    [error  ][aot] An error has occurred while processing the AOT cache. Run with -Xlog:aot for details.
   log:    [error  ][aot] shared class paths mismatch (hint: enable -Xlog:class+path=info to diagnose the failure)
   log:    [error  ][aot] Unable to map shared spaces

== the application directory was moved after training (same bytes, different path)
   result:  started, ready after 2005 ms   (Started AotCacheApplication in 1.542 seconds)
   log:     (nothing at warning or error level)

== cache trained on the fat jar, run from the extracted layout
   result:  started, ready after 3900 ms   (Started AotCacheApplication in 3.262 seconds)
   log:    [warning][aot] This file is not the one used while building the AOT cache: 'app.jar', size has changed
   log:    [error  ][aot] An error has occurred while processing the AOT cache. Run with -Xlog:aot for details.
   log:    [error  ][aot] shared class paths mismatch (hint: enable -Xlog:class+path=info to diagnose the failure)
   log:    [error  ][aot] Unable to map shared spaces

== JDK 25's cache used by JDK 27
   result:  started, ready after 4221 ms   (Started AotCacheApplication in 3.537 seconds)
   log:    [warning][aot] The AOT cache version 0x13 does not match the required version 0x14.
   log:    [warning][aot] The AOT cache has the wrong version.
   log:    [error  ][aot] An error has occurred while processing the AOT cache. Run with -Xlog:aot for details.
   log:    [error  ][aot] Loading static archive failed.
   log:    [warning][aot] The AOT cache version 0x13 does not match the required version 0x14.

== the same, with -XX:AOTMode=on
   result:  did not start (exit code 1)
   log:    [warning][aot] The AOT cache version 0x13 does not match the required version 0x14.
   log:    [warning][aot] The AOT cache has the wrong version.
   log:    [error  ][aot] An error has occurred while processing the AOT cache. Run with -Xlog:aot for details.
   log:    [error  ][aot] Loading static archive failed.
   log:    [warning][aot] The AOT cache version 0x13 does not match the required version 0x14.

== -XX:+UseCompactObjectHeaders added at run time only (JDK 25)
   result:  started, ready after 4138 ms   (Started AotCacheApplication in 3.446 seconds)
   log:    [warning][aot] Unable to use AOT cache.
   log:    [error  ][aot] An error has occurred while processing the AOT cache. Run with -Xlog:aot for details.
   log:    [error  ][aot] Loading static archive failed.
   log:    [error  ][aot] Unable to map shared spaces

== a different collector at run time: -XX:+UseSerialGC
   result:  started, ready after 1916 ms   (Started AotCacheApplication in 1.516 seconds)
   log:     (nothing at warning or error level)

== a different collector at run time: -XX:+UseParallelGC
   result:  started, ready after 1957 ms   (Started AotCacheApplication in 1.473 seconds)
   log:     (nothing at warning or error level)

== a different collector at run time: -XX:+UseZGC
   result:  started, ready after 3981 ms   (Started AotCacheApplication in 3.347 seconds)
   log:    [warning][aot] Unable to use AOT cache.
[                    ] The saved state of UseCompressedOops and UseCompressedClassPointers is different from runtime, CDS will be disabled.
   log:    [error  ][aot] An error has occurred while processing the AOT cache. Run with -Xlog:aot for details.
   log:    [error  ][aot] Loading static archive failed.
   log:    [error  ][aot] Unable to map shared spaces

== a different heap size at run time: -Xmx256m
   result:  started, ready after 2058 ms   (Started AotCacheApplication in 1.602 seconds)
   log:     (nothing at warning or error level)

== a cache file that does not exist
   result:  started, ready after 4113 ms   (Started AotCacheApplication in 3.451 seconds)
   log:    [error][aot] An error has occurred while processing the AOT cache. Run with -Xlog:aot for details.
   log:    [error][aot] Loading static archive failed.
   log:    [error][aot] Unable to map shared spaces

== a cache file that does not exist, with -XX:AOTMode=on
   result:  did not start (exit code 1)
   log:    [error][aot] An error has occurred while processing the AOT cache. Run with -Xlog:aot for details.
   log:    [error][aot] Loading static archive failed.
   log:    [error][aot] Unable to map shared spaces

# and on JDK 27, whose cache was trained under the default collector (G1):

== JDK 27, cache from JDK 27 (control)
   result:  started, ready after 1955 ms   (Started AotCacheApplication in 1.547 seconds)
   log:     (nothing at warning or error level)

== JDK 27, -XX:+UseZGC at run time
   result:  started, ready after 4158 ms   (Started AotCacheApplication in 3.502 seconds)
   log:    [warning][aot] Unable to use AOT cache.
[                    ] The saved state of UseCompressedOops (1) is different from runtime (0), CDS will be disabled.
   log:    [error  ][aot] An error has occurred while processing the AOT cache. Run with -Xlog:aot for details.
   log:    [error  ][aot] Loading static archive failed.
   log:    [error  ][aot] Unable to map shared spaces

== JDK 27, -XX:+UseSerialGC at run time
   result:  started, ready after 2103 ms   (Started AotCacheApplication in 1.672 seconds)
   log:     (nothing at warning or error level)

== JDK 27, -XX:-UseCompactObjectHeaders at run time
   result:  started, ready after 3906 ms   (Started AotCacheApplication in 3.163 seconds)
   log:    [warning][aot] Unable to use AOT cache.
   log:    [error  ][aot] An error has occurred while processing the AOT cache. Run with -Xlog:aot for details.
   log:    [error  ][aot] Loading static archive failed.
   log:    [warning][aot] Unable to use AOT cache.
   log:    [error  ][aot] Loading static archive failed.

# why ZGC is different: ask the JVM (-Xlog:aot=info) why it refused the G1-trained cache

== JDK 27, -XX:+UseZGC with the G1-trained cache, -Xlog:aot=info
   result:  started, ready after 3885 ms   (Started AotCacheApplication in 3.258 seconds)
   log:    [info][aot] The AOT cache was created with UseCompressedOops = 1, UseCompactObjectHeaders = 1
   log:    [warning][aot] Unable to use AOT cache.
[                    ] The saved state of UseCompressedOops (1) is different from runtime (0), CDS will be disabled.
   log:    [error  ][aot] An error has occurred while processing the AOT cache. Run with -Xlog:aot for details.
   log:    [error  ][aot] Loading static archive failed.

== JDK 27, cache trained under ZGC, run under ZGC
   result:  started, ready after 1988 ms   (Started AotCacheApplication in 1.554 seconds)
   log:     (nothing at warning or error level)

== JDK 27, cache trained under ZGC, run under G1 (compressed oops on again)
   result:  started, ready after 3869 ms   (Started AotCacheApplication in 3.199 seconds)
   log:    [warning][aot] Unable to use AOT cache.
[                    ] The saved state of UseCompressedOops (0) is different from runtime (1), CDS will be disabled.
   log:    [error  ][aot] An error has occurred while processing the AOT cache. Run with -Xlog:aot for details.
   log:    [error  ][aot] Loading static archive failed.
   log:    [warning][aot] Unable to use AOT cache.

== JDK 27, cache trained under ZGC, run under G1 with -XX:-UseCompressedOops
   result:  started, ready after 2018 ms   (Started AotCacheApplication in 1.534 seconds)
   log:     (nothing at warning or error level)