Actuator heapdump endpoint is failing on modern OpenJ9 JVMs

[DRoppelt]

Hi there,

with spring boot 3.4.6 (also verified with 3.5.0), I cannot instruct actuator to give me a heapdump when running in a Semeru (Openj9) runtime

I found these tickets that suggest that heapdumping did not always work but was added for openj9

#26466

#27533

To reproduce: use attached project (based on https://start.spring.io/#!type=maven-project&language=java&platformVersion=3.5.0&packaging=jar&jvmVersion=21&groupId=com.example&artifactId=demo&name=demo&description=Demo%20project%20for%20Spring%20Boot&packageName=com.example.demo&dependencies=actuator,web)

openj9-threaddump.zip

mvn clean install

Then use your favorite tooling to run the image via the included Dockerfile

FROM ibm-semeru-runtimes:open-21.0.7_6-jdk-noble

COPY target/*.jar /app.jar
EXPOSE 8080
ENTRYPOINT ["java", "-jar", "/app.jar"]

probe the container with

curl localhost:8080/actuator/threaddump

observer that no filestream is returned but instead you see following in the logs

Whitelabel Error Page

This application has no explicit mapping for /error, so you are seeing this as a fallback.
Mon Jun 16 11:17:31 UTC 2025
There was an unexpected error (type=Internal Server Error, status=500).

note ExtendedHotSpotDiagnostic ... at jdk.management/com.sun.management.internal.ExtendedHotSpotDiagnostic.dumpHeap(ExtendedHotSpotDiagnostic.java:60) ~[na:na]

2025-06-16T11:17:31.111Z ERROR 1 --- [demo] [nio-8080-exec-4] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed: java.lang.UnsupportedOperationException] with root cause
2025-06-16T11:17:31.116198440Z 
2025-06-16T11:17:31.116209107Z java.lang.UnsupportedOperationException: null
2025-06-16T11:17:31.116212607Z 	at jdk.management/com.sun.management.internal.ExtendedHotSpotDiagnostic.dumpHeap(ExtendedHotSpotDiagnostic.java:60) ~[na:na]
2025-06-16T11:17:31.116215524Z 	at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103) ~[na:na]
2025-06-16T11:17:31.116218649Z 	at java.base/java.lang.reflect.Method.invoke(Method.java:586) ~[na:na]
2025-06-16T11:17:31.116221190Z 	at org.springframework.util.ReflectionUtils.invokeMethod(ReflectionUtils.java:281) ~[spring-core-6.2.7.jar!/:6.2.7]
2025-06-16T11:17:31.116223607Z 	at org.springframework.boot.actuate.management.HeapDumpWebEndpoint$HotSpotDiagnosticMXBeanHeapDumper.dumpHeap(HeapDumpWebEndpoint.java:172) ~[spring-boot-actuator-3.5.0.jar!/:3.5.0]
2025-06-16T11:17:31.116226440Z 	at org.springframework.boot.actuate.management.HeapDumpWebEndpoint.dumpHeap(HeapDumpWebEndpoint.java:105) ~[spring-boot-actuator-3.5.0.jar!/:3.5.0]
2025-06-16T11:17:31.116228815Z 	at org.springframework.boot.actuate.management.HeapDumpWebEndpoint.heapDump(HeapDumpWebEndpoint.java:82) ~[spring-boot-actuator-3.5.0.jar!/:3.5.0]
2025-06-16T11:17:31.117094690Z 	at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103) ~[na:na]
2025-06-16T11:17:31.117109107Z 	at java.base/java.lang.reflect.Method.invoke(Method.java:586) ~[na:na]
2025-06-16T11:17:31.117111524Z 	at org.springframework.util.ReflectionUtils.invokeMethod(ReflectionUtils.java:281) ~[spring-core-6.2.7.jar!/:6.2.7]
2025-06-16T11:17:31.117113565Z 	at org.springframework.boot.actuate.endpoint.invoke.reflect.ReflectiveOperationInvoker.invoke(ReflectiveOperationInvoker.java:74) ~[spring-boot-actuator-3.5.0.jar!/:3.5.0]
2025-06-16T11:17:31.117115607Z 	at org.springframework.boot.actuate.endpoint.annotation.AbstractDiscoveredOperation.invoke(AbstractDiscoveredOperation.java:60) ~[spring-boot-actuator-3.5.0.jar!/:3.5.0]
2025-06-16T11:17:31.117120232Z 	at org.springframework.boot.actuate.endpoint.web.servlet.AbstractWebMvcEndpointHandlerMapping$ServletWebOperationAdapter.handle(AbstractWebMvcEndpointHandlerMapping.java:327) ~[spring-boot-actuator-3.5.0.jar!/:3.5.0]
2025-06-16T11:17:31.117122399Z 	at org.springframework.boot.actuate.endpoint.web.servlet.AbstractWebMvcEndpointHandlerMapping$OperationHandler.handle(AbstractWebMvcEndpointHandlerMapping.java:434) ~[spring-boot-actuator-3.5.0.jar!/:3.5.0]
2025-06-16T11:17:31.117124357Z 	at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103) ~[na:na]
2025-06-16T11:17:31.117126190Z 	at java.base/java.lang.reflect.Method.invoke(Method.java:586) ~[na:na]
2025-06-16T11:17:31.117127940Z 	at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:258) ~[spring-web-6.2.7.jar!/:6.2.7]
2025-06-16T11:17:31.117129899Z 	at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:191) ~[spring-web-6.2.7.jar!/:6.2.7]
2025-06-16T11:17:31.117132732Z 	at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:118) ~[spring-webmvc-6.2.7.jar!/:6.2.7]
2025-06-16T11:17:31.117134607Z 	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:986) ~[spring-webmvc-6.2.7.jar!/:6.2.7]
2025-06-16T11:17:31.117136440Z 	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:891) ~[spring-webmvc-6.2.7.jar!/:6.2.7]
2025-06-16T11:17:31.117138357Z 	at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-6.2.7.jar!/:6.2.7]
2025-06-16T11:17:31.117140482Z 	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1089) ~[spring-webmvc-6.2.7.jar!/:6.2.7]
2025-06-16T11:17:31.117142690Z 	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:979) ~[spring-webmvc-6.2.7.jar!/:6.2.7]
2025-06-16T11:17:31.117148315Z 	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1014) ~[spring-webmvc-6.2.7.jar!/:6.2.7]
2025-06-16T11:17:31.117164857Z 	at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:903) ~[spring-webmvc-6.2.7.jar!/:6.2.7]
2025-06-16T11:17:31.117168232Z 	at jakarta.servlet.http.HttpServlet.service(HttpServlet.java:564) ~[tomcat-embed-core-10.1.41.jar!/:na]
2025-06-16T11:17:31.117170440Z 	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:885) ~[spring-webmvc-6.2.7.jar!/:6.2.7]
2025-06-16T11:17:31.117172440Z 	at jakarta.servlet.http.HttpServlet.service(HttpServlet.java:658) ~[tomcat-embed-core-10.1.41.jar!/:na]
2025-06-16T11:17:31.117174149Z 	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:195) ~[tomcat-embed-core-10.1.41.jar!/:na]
2025-06-16T11:17:31.117175899Z 	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:140) ~[tomcat-embed-core-10.1.41.jar!/:na]
2025-06-16T11:17:31.117177857Z 	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51) ~[tomcat-embed-websocket-10.1.41.jar!/:na]
2025-06-16T11:17:31.117179565Z 	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:164) ~[tomcat-embed-core-10.1.41.jar!/:na]
2025-06-16T11:17:31.117181357Z 	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:140) ~[tomcat-embed-core-10.1.41.jar!/:na]
2025-06-16T11:17:31.117183107Z 	at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-6.2.7.jar!/:6.2.7]
2025-06-16T11:17:31.117184815Z 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116) ~[spring-web-6.2.7.jar!/:6.2.7]
2025-06-16T11:17:31.117186524Z 	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:164) ~[tomcat-embed-core-10.1.41.jar!/:na]
2025-06-16T11:17:31.117188274Z 	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:140) ~[tomcat-embed-core-10.1.41.jar!/:na]
2025-06-16T11:17:31.117189982Z 	at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-6.2.7.jar!/:6.2.7]
2025-06-16T11:17:31.117191774Z 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116) ~[spring-web-6.2.7.jar!/:6.2.7]
2025-06-16T11:17:31.117193482Z 	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:164) ~[tomcat-embed-core-10.1.41.jar!/:na]
2025-06-16T11:17:31.117195690Z 	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:140) ~[tomcat-embed-core-10.1.41.jar!/:na]
2025-06-16T11:17:31.117197482Z 	at org.springframework.web.filter.ServerHttpObservationFilter.doFilterInternal(ServerHttpObservationFilter.java:114) ~[spring-web-6.2.7.jar!/:6.2.7]
2025-06-16T11:17:31.117199274Z 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116) ~[spring-web-6.2.7.jar!/:6.2.7]
2025-06-16T11:17:31.117200982Z 	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:164) ~[tomcat-embed-core-10.1.41.jar!/:na]
2025-06-16T11:17:31.117211649Z 	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:140) ~[tomcat-embed-core-10.1.41.jar!/:na]
2025-06-16T11:17:31.117214482Z 	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-6.2.7.jar!/:6.2.7]
2025-06-16T11:17:31.117216274Z 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116) ~[spring-web-6.2.7.jar!/:6.2.7]
2025-06-16T11:17:31.117217940Z 	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:164) ~[tomcat-embed-core-10.1.41.jar!/:na]
2025-06-16T11:17:31.117219607Z 	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:140) ~[tomcat-embed-core-10.1.41.jar!/:na]
2025-06-16T11:17:31.117221274Z 	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:167) ~[tomcat-embed-core-10.1.41.jar!/:na]
2025-06-16T11:17:31.117222940Z 	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:90) ~[tomcat-embed-core-10.1.41.jar!/:na]
2025-06-16T11:17:31.117224565Z 	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:483) ~[tomcat-embed-core-10.1.41.jar!/:na]
2025-06-16T11:17:31.117226232Z 	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:116) ~[tomcat-embed-core-10.1.41.jar!/:na]
2025-06-16T11:17:31.117227899Z 	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:93) ~[tomcat-embed-core-10.1.41.jar!/:na]
2025-06-16T11:17:31.117229524Z 	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) ~[tomcat-embed-core-10.1.41.jar!/:na]
2025-06-16T11:17:31.117231190Z 	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:344) ~[tomcat-embed-core-10.1.41.jar!/:na]
2025-06-16T11:17:31.117235607Z 	at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:398) ~[tomcat-embed-core-10.1.41.jar!/:na]
2025-06-16T11:17:31.117237315Z 	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:63) ~[tomcat-embed-core-10.1.41.jar!/:na]
2025-06-16T11:17:31.117239024Z 	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:903) ~[tomcat-embed-core-10.1.41.jar!/:na]
2025-06-16T11:17:31.117240732Z 	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1740) ~[tomcat-embed-core-10.1.41.jar!/:na]
2025-06-16T11:17:31.117242399Z 	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:52) ~[tomcat-embed-core-10.1.41.jar!/:na]
2025-06-16T11:17:31.117244107Z 	at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1189) ~[tomcat-embed-core-10.1.41.jar!/:na]
2025-06-16T11:17:31.117245940Z 	at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:658) ~[tomcat-embed-core-10.1.41.jar!/:na]
2025-06-16T11:17:31.117247607Z 	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:63) ~[tomcat-embed-core-10.1.41.jar!/:na]
2025-06-16T11:17:31.117252524Z 	at java.base/java.lang.Thread.run(Thread.java:1595) ~[na:na]
2025-06-16T11:17:31.117255315Z 

it appears that this block never throws the exception to then fallback to the OpenJ9 implementation

spring-boot/spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/management/HeapDumpWebEndpoint.java

Lines 114 to 121 in 1ae0548

	protected HeapDumper createHeapDumper() throws HeapDumperUnavailableException {
	try {
	return new HotSpotDiagnosticMXBeanHeapDumper();
	}
	catch (HeapDumperUnavailableException ex) {
	return new OpenJ9DiagnosticsMXBeanHeapDumper();
	}
	}

[DRoppelt]

It appears that the openj9 project has added some classes since 21

https://github.com/eclipse-openj9/openj9/blob/f255919f1f639eb4b64238b12e5fcd5e03320565/jcl/src/jdk.management/share/classes/com/ibm/lang/management/internal/PlatformMBeanProvider.java#L38-L41

(see eclipse-openj9/openj9#17634)

/*[IF JAVA_SPEC_VERSION >= 21]*/
import com.sun.management.internal.ExtendedHotSpotDiagnostic;
import com.sun.management.HotSpotDiagnosticMXBean;
/*[ENDIF] JAVA_SPEC_VERSION >= 21 */

Which breaks the assumption that the hotspot dumper will throw an exception here when looking up com.sun.management.HotSpotDiagnosticMXBean

spring-boot/spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/management/HeapDumpWebEndpoint.java

Lines 157 to 166 in 1ae0548

	Class<?> diagnosticMXBeanClass = ClassUtils
	.resolveClassName("com.sun.management.HotSpotDiagnosticMXBean", null);
	this.diagnosticMXBean = ManagementFactory
	.getPlatformMXBean((Class<PlatformManagedObject>) diagnosticMXBeanClass);
	this.dumpHeapMethod = ReflectionUtils.findMethod(diagnosticMXBeanClass, "dumpHeap", String.class,
	Boolean.TYPE);
	}
	catch (Throwable ex) {
	throw new HeapDumperUnavailableException("Unable to locate HotSpotDiagnosticMXBean", ex);
	}

        protected HotSpotDiagnosticMXBeanHeapDumper() {
            try {
                Class<?> diagnosticMXBeanClass = ClassUtils.resolveClassName("com.sun.management.HotSpotDiagnosticMXBean", (ClassLoader)null);
                this.diagnosticMXBean = ManagementFactory.getPlatformMXBean(diagnosticMXBeanClass);
                this.dumpHeapMethod = ReflectionUtils.findMethod(diagnosticMXBeanClass, "dumpHeap", new Class[]{String.class, Boolean.TYPE});
            } catch (Throwable ex) {
                throw new HeapDumperUnavailableException("Unable to locate HotSpotDiagnosticMXBean", ex);
            }
        }

[mhalbritter]

We could either find a different class which is not there when running on OpenJ9, or we could use System properties to find out if we're running on OpenJ9:

java.vm.name = Eclipse OpenJ9 VM
java.vm.vendor = Eclipse OpenJ9
openj9.compiler = j9jit29

[DRoppelt]

another 2 ideas:

1. try the openj9 lookup and if that one succeeds, take that one. It looksup openj9.lang.management.OpenJ9DiagnosticsMXBean which is safe to assume to be absent in hotspot. But that would likely add overhead for the hotspot users (?). Since it is lazily created (and then remains as singleton) upon /heapdump, that might be ignored?

2. possibly an explicit opt-in via properties management.endpoint.heapdump.dumper=openj9

Regarding system-props, here is what the container logs out for System.getProperties() within that container using ibm-semeru-runtimes:open-21.0.7_6-jdk-noble image. I agree with the 3 properties you pinpointed

    public HelloController() {
        log.info("Hello World! {}", System.getProperties());

    }

HelloController         : Hello World! {awt.toolkit=sun.awt.X11.XToolkit, jdk.extensions.version=21.0.7.0, java.specification.version=21, sun.jnu.encoding=UTF-8, java.class.path=/app.jar, java.vm.vendor=Eclipse OpenJ9, sun.arch.data.model=64, com.ibm.vm.bitmode=64, com.ibm.oti.vm.library.version=29, java.vendor.url=https://www.ibm.com/semeru-runtimes, catalina.useNaming=false, user.timezone=Etc/UTC, jfr.unsupported.vm=true, java.vm.specification.version=21, os.name=Linux, APPLICATION_NAME=demo, sun.java.launcher=SUN_STANDARD, user.country=US, sun.boot.library.path=/opt/java/openjdk/lib/default:/opt/java/openjdk/lib, sun.java.command=/app.jar, jdk.debug=release, sun.cpu.endian=little, user.home=/root, user.language=en, java.specification.vendor=Oracle Corporation, java.version.date=2025-04-15, java.home=/opt/java/openjdk, ibm.signalhandling.rs=false, openjdk.methodhandles=true, jdk.extensions.name=Extensions for OpenJDK for Eclipse OpenJ9, file.separator=/, line.separator=
2025-06-16T13:08:08.804982189Z , java.specification.name=Java Platform API Specification, java.vm.specification.vendor=Oracle Corporation, FILE_LOG_CHARSET=UTF-8, com.ibm.util.extralibs.properties=, java.awt.graphicsenv=sun.awt.X11GraphicsEnvironment, java.awt.headless=true, com.ibm.oti.configuration=scar, java.awt.fonts=, com.ibm.oti.shared.enabled=true, com.ibm.oti.vm.bootstrap.library.path=/opt/java/openjdk/lib/default:/opt/java/openjdk/lib, com.ibm.cpu.endian=little, java.protocol.handler.pkgs=org.springframework.boot.loader.net.protocol, java.fullversion=21.0.7+6-LTS
2025-06-16T13:08:08.804985647Z JRE 21 Linux aarch64-64-Bit Compressed References 20250415_443 (JIT enabled, AOT enabled)
2025-06-16T13:08:08.804986731Z OpenJ9   - 31cf5538b0
2025-06-16T13:08:08.804987647Z OMR      - 9bcff94a2
2025-06-16T13:08:08.804989939Z JCL      - 26c2dc3d801 based on jdk-21.0.7+6, java.runtime.version=21.0.7+6-LTS, user.name=root, stdout.encoding=UTF-8, path.separator=:, os.version=6.12.28-0-virt, java.runtime.name=IBM Semeru Runtime Open Edition, ibm.signalhandling.sigint=true, org.eclipse.openj9.criu.isCRaCCapable=true, file.encoding=UTF-8, org.eclipse.openj9.criu.isCRIUCapable=true, java.vm.name=Eclipse OpenJ9 VM, openj9.compiler=j9jit29, java.vendor.version=21.0.7.0, ibm.signalhandling.sigchain=true, java.vendor.url.bug=https://github.com/ibmruntimes/Semeru-Runtimes/issues, java.io.tmpdir=/tmp, catalina.home=/tmp/tomcat.8080.16916605689682572145, java.version=21.0.7, com.ibm.system.agent.path=/opt/java/openjdk/lib, user.dir=/, os.arch=aarch64, org.eclipse.openj9.jfr.isJFREnabled=true, java.vm.specification.name=Java Virtual Machine Specification, PID=1, java.awt.printerjob=sun.print.PSPrinterJob, os.encoding=UTF-8, CONSOLE_LOG_CHARSET=UTF-8, catalina.base=/tmp/tomcat.8080.16916605689682572145, native.encoding=UTF-8, java.library.path=/opt/java/openjdk/lib/default:/opt/java/openjdk/lib:/usr/lib64:/usr/lib, java.vm.info=JRE 21 Linux aarch64-64-Bit Compressed References 20250415_443 (JIT enabled, AOT enabled)
2025-06-16T13:08:08.804992397Z OpenJ9   - 31cf5538b0
2025-06-16T13:08:08.804993189Z OMR      - 9bcff94a2
2025-06-16T13:08:08.804993981Z JCL      - 26c2dc3d801 based on jdk-21.0.7+6, stderr.encoding=UTF-8, java.vendor=IBM Corporation, java.vm.version=openj9-0.51.0, ibm.system.encoding=UTF-8, com.ibm.jcl.checkClassPath=, java.lang.invoke.VarHandle.VAR_HANDLE_GUARDS=false, sun.io.unicode.encoding=UnicodeLittle, java.class.version=65.0, LOGGED_APPLICATION_NAME=[demo] }

[DRoppelt]

try the openj9 lookup and if that one succeeds, take that one. It looksup openj9.lang.management.OpenJ9DiagnosticsMXBean which is safe to assume to be absent in hotspot. But that would likely add overhead for the hotspot users (?). Since it is lazily created (and then remains as singleton) upon /heapdump, that might be ignored?

Changing the order from

 protected HeapDumper createHeapDumper() throws HeapDumperUnavailableException { 
 	try { 
 		return new HotSpotDiagnosticMXBeanHeapDumper(); 
 	} 
 	catch (HeapDumperUnavailableException ex) { 
 		return new OpenJ9DiagnosticsMXBeanHeapDumper(); 
 	} 
 } 

to

 protected HeapDumper createHeapDumper() throws HeapDumperUnavailableException { 
 	try { 
 		return new OpenJ9DiagnosticsMXBeanHeapDumper(); 
 	} 
 	catch (HeapDumperUnavailableException ex) { 
 		return new HotSpotDiagnosticMXBeanHeapDumper(); 
 	} 
 } 

should already do the trick if that is a path we would like to take