Using AOTCaching with debug (JDWP)

ioi.lam at oracle.com ioi.lam at oracle.com
Tue Jan 27 07:27:21 UTC 2026 

When JDWP is used, AOT is disabled by this check:

https://github.com/openjdk/jdk/blob/cba7d88ca427984ebb27a1634aab10a62c9eede1/src/hotspot/share/cds/filemap.cpp#L1743-L1748

The reason we have this check is that when -XX:+AOTClassLinking is 
enabled (by default in AOT cache creation), some class initializers are 
executed in the AOT assembly phase, and are not executed in the 
production run.

As a result, some breakpoints will not work.

Here's an example. I have rebuilt the JVM to disable the above check:


===============================================================================

Without AOT cache: you can break at java.lang.invoke.Invokers.<clinit>

===============================================================================
$ jdb -launch -classpath HelloWorld.jar -R-XX:AOTMode=off 
-R-XX:AOTCache=hw.aot java.lang.invoke.Invokers
Set uncaught java.lang.Throwable
Set deferred uncaught java.lang.Throwable
Initializing jdb ...
 >
VM Started: No frames on the current call stack

main[1] stop in java.lang.invoke.Invokers.<clinit>
Deferring breakpoint java.lang.invoke.Invokers.<clinit>.
It will be set after the class is loaded.
main[1] cont
 > Set deferred breakpoint java.lang.invoke.Invokers.<clinit>

Breakpoint hit: "thread=main", java.lang.invoke.Invokers.<clinit>(), 
line=47 bci=0

main[1] where
   [1] java.lang.invoke.Invokers.<clinit> (Invokers.java:47)
   [2] java.lang.invoke.MethodHandleNatives.linkCallSiteImpl 
(MethodHandleNatives.java:263)
   [3] java.lang.invoke.MethodHandleNatives.linkCallSite 
(MethodHandleNatives.java:240)
   [4] java.util.ResourceBundle$Control.<clinit> (ResourceBundle.java:2,833)
   [5] java.util.ResourceBundle.getDefaultControl 
(ResourceBundle.java:1,508)
   [6] java.util.ResourceBundle.getDefaultControl 
(ResourceBundle.java:1,503)
   [7] java.util.ResourceBundle.getBundle (ResourceBundle.java:863)
   [8] sun.launcher.LauncherHelper$ResourceBundleHolder.<clinit> 
(LauncherHelper.java:124)
   [9] sun.launcher.LauncherHelper.getLocalizedMessage 
(LauncherHelper.java:532)
   [10] sun.launcher.LauncherHelper.abort (LauncherHelper.java:720)
   [11] sun.launcher.LauncherHelper.validateMainMethod 
(LauncherHelper.java:944)
   [12] sun.launcher.LauncherHelper.checkAndLoadMain 
(LauncherHelper.java:778)
main[1] cont
 > Error: Main method not found in class java.lang.invoke.Invokers, 
please define the main method as:
    public static void main(String[] args)
or a JavaFX application class must extend javafx.application.Application

The application exited

===============================================================================

With AOT cache: you cannot break at java.lang.invoke.Invokers.<clinit>

===============================================================================


$ jdb -launch -classpath HelloWorld.jar -R-XX:AOTMode=on 
-R-XX:AOTCache=hw.aot java.lang.invoke.Invokers
Set uncaught java.lang.Throwable
Set deferred uncaught java.lang.Throwable
Initializing jdb ...
 >
VM Started: No frames on the current call stack

main[1] stop in java.lang.invoke.Invokers.<clinit>
Set breakpoint java.lang.invoke.Invokers.<clinit>
main[1] cont
 > Error: Main method not found in class java.lang.invoke.Invokers, 
please define the main method as:
    public static void main(String[] args)
or a JavaFX application class must extend javafx.application.Application

The application exited


On 1/26/26 9:39 PM, Anthony Dahanne wrote:
> Hello all!
> I'm trying to run an AOTCaching optimized app in debug mode; 
> unfortunately, it does not seem to be supported.
>
> Using a JDK 25.0.1, during the training run I have:
>
> ```
>  [creator]     Temporary AOTConfiguration recorded: application.aot.config
>     [creator]     Launching child process 
> /layers/paketo-buildpacks_bellsoft-liberica/jre/bin/java to assemble 
> AOT cache application.aot using configuration application.aot.config
>     [creator]     Picked up JAVA_TOOL_OPTIONS: 
> -Djava.class.path=runner.jar:lib/spring-cloud-bindings-2.0.4.jar 
> -agentlib:jdwp=transport=dt_socket,server=y,address=*:8000,suspend=n 
> -XX:+AOTClassLinking -Dspring.context.exit=onRefresh 
> -XX:AOTCacheOutput=application.aot 
> -XX:AOTConfiguration=application.aot.config -XX:AOTMode=create
>     [creator]     Reading AOTConfiguration application.aot.config and 
> writing AOTCache application.aot
>     [creator]     [0.262s][warning][aot] Skipping 
> io/micrometer/core/instrument/config/InvalidConfigurationException: 
> Unlinked class not supported by AOTClassLinking
>     [creator]     [0.262s][warning][aot] Skipping 
> org/springframework/web/servlet/view/freemarker/FreeMarkerView: 
> Unlinked class not supported by AOTClassLinking
>     [creator]     [0.262s][warning][aot] Skipping 
> org/springframework/boot/logging/log4j2/Log4J2LoggingSystem: Unlinked 
> class not supported by AOTClassLinking
>     [creator]     [0.263s][warning][aot] Skipping 
> org/springframework/core/ReactiveAdapterRegistry$ReactorAdapter: 
> Unlinked class not supported by AOTClassLinking
>     [creator]     AOTCache creation is complete: application.aot 
> 56819712 bytes
>     [creator]     Removed temporary AOT configuration file 
> application.aot.config
> ```
>
> but at runtime, I have:
> ```
> Picked up JAVA_TOOL_OPTIONS: 
> -Djava.security.properties=/layers/paketo-buildpacks_bellsoft-liberica/java-security-properties/java-security.properties 
> -XX:+ExitOnOutOfMemoryError 
> -agentlib:jdwp=transport=dt_socket,server=y,address=*:8000,suspend=n 
> -XX:MaxDirectMemorySize=10M -Xmx14945375K -XX:MaxMetaspaceSize=78944K 
> -XX:ReservedCodeCacheSize=240M -Xss1M -XX:+UnlockDiagnosticVMOptions 
> -XX:NativeMemoryTracking=summary -XX:+PrintNMTStatistics 
> -XX:AOTCache=application.aot 
> -Dorg.springframework.cloud.bindings.boot.enable=true
> [0.032s][error][aot] AOT cache has aot-linked classes. It cannot be 
> used with JDWP agent
> [0.034s][error][aot] An error has occurred while processing the AOT 
> cache. Run with -Xlog:aot for details.
> [0.034s][error][aot] Unable to map shared spaces
> Listening for transport dt_socket at address: 8000
> ```
>
> If I enable `-Xlog:aot` at runtime, I have:
>
> ```
> Picked up JAVA_TOOL_OPTIONS: -Xlog:aot 
> -Djava.security.properties=/layers/paketo-buildpacks_bellsoft-liberica/java-security-properties/java-security.properties 
> -XX:+ExitOnOutOfMemoryError 
> -agentlib:jdwp=transport=dt_socket,server=y,address=*:8000,suspend=n 
> -XX:MaxDirectMemorySize=10M -Xmx15196043K -XX:MaxMetaspaceSize=78944K 
> -XX:ReservedCodeCacheSize=240M -Xss1M -XX:+UnlockDiagnosticVMOptions 
> -XX:NativeMemoryTracking=summary -XX:+PrintNMTStatistics 
> -XX:AOTCache=application.aot 
> -Dorg.springframework.cloud.bindings.boot.enable=true
> [0.033s][info][aot] trying to map application.aot
> [0.033s][info][aot] Opened AOT cache application.aot.
> [0.033s][info][aot] The AOT cache was created with UseCompressedOops = 
> 1, UseCompressedClassPointers = 1, UseCompactObjectHeaders = 0
> [0.033s][info][aot] Core region alignment: 65536
> [0.033s][info][aot] ArchiveRelocationMode: 1
> [0.033s][info][aot] ArchiveRelocationMode == 1: always map archive(s) 
> at an alternative address
> [0.033s][info][aot] Try to map archive(s) at an alternative address
> [0.033s][info][aot] Reserved archive_space_rs [0x0000003000000000 - 
> 0x0000003004000000] (67108864) bytes (includes protection zone)
> [0.033s][info][aot] Reserved class_space_rs [0x0000003004000000 - 
> 0x0000003008000000] (67108864) bytes
> [0.033s][info][aot] Mapped static  region #0 at base 
> 0x0000003000010000 top 0x0000003001500000 (ReadWrite)
> [0.033s][info][aot] Mapped static  region #1 at base 
> 0x0000003001500000 top 0x0000003003200000 (ReadOnly)
> [0.033s][info][aot] Mapped static  region #2 at base 
> 0x0000ffff5c120000 top 0x0000ffff5c1e0000 (Bitmap)
> [0.069s][info][aot] archived module property jdk.module.main: (null)
> [0.069s][info][aot] archived module property jdk.module.addexports: (null)
> [0.069s][info][aot] archived module property jdk.module.addmods: (null)
> [0.069s][info][aot] archived module property 
> jdk.module.enable.native.access: (null)
> [0.069s][info][aot] archived module property jdk.module.addopens: (null)
> [0.069s][info][aot] archived module property jdk.module.addreads: (null)
> [0.069s][info][aot] optimized module handling: enabled
> [0.069s][info][aot] full module graph: enabled
> [0.069s][error][aot] AOT cache has aot-linked classes. It cannot be 
> used with JDWP agent
> [0.069s][info ][aot] Unmapping region #0 at base 0x0000003000010000 
> (ReadWrite)
> [0.069s][info ][aot] Region #0 (ReadWrite) is in a reserved space, it 
> will be freed when the space is released
> [0.069s][info ][aot] Unmapping region #1 at base 0x0000003001500000 
> (ReadOnly)
> [0.069s][info ][aot] Region #1 (ReadOnly) is in a reserved space, it 
> will be freed when the space is released
> [0.069s][info ][aot] Unmapping region #2 at base 0x0000ffff5c120000 
> (Bitmap)
> [0.069s][error][aot] An error has occurred while processing the AOT 
> cache. Run with -Xlog:aot for details.
> [0.069s][error][aot] Unable to map shared spaces
> Listening for transport dt_socket at address: 8000
> ```
>
> I have tried several variations using ` -XX:+AOTClassLinking` during 
> the training run, but that did not change a thing.
>
> Is it possible to use AOTCaching when debug is enabled?
>
> Thank you!
>
>

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