Can't get a Java heapdump from a docker container

Question

My Java process is stuck and hogging a lot of CPU on the VM. I am trying to get to the root of the issue by getting a heapdump. This process is running in a docker container. I am getting into the container and running a jmap -F -dump:format=b,file=/tmp/heapdump.bin 6 as root user. But I still get java.lang.reflect.InvocationTargetException.

I used jmap -F to get over this exception - com.sun.tools.attach.AttachNotSupportedException: Unable to open socket file: target process not responding or HotSpot VM not loaded

I referenced the this post to make modifications to my query - Running jmap getting Unable to open socket file, I have tried both jmap and jcmd queries, but got the same results.

Can someone please help here?

# jmap -F -dump:format=b,file=/tmp/heapdump.bin 6
Attaching to process ID 6, please wait...
Debugger attached successfully.
Server compiler detected.
JVM version is 25.111-b14
Dumping heap to /tmp/heapdump.bin ...
Exception in thread "main" java.lang.reflect.InvocationTargetException
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at sun.tools.jmap.JMap.runTool(JMap.java:201)
    at sun.tools.jmap.JMap.main(JMap.java:130)
Caused by: java.lang.InternalError: Metadata does not appear to be polymorphic
    at sun.jvm.hotspot.types.basic.BasicTypeDataBase.findDynamicTypeForAddress(BasicTypeDataBase.java:278)
    at sun.jvm.hotspot.runtime.VirtualBaseConstructor.instantiateWrapperFor(VirtualBaseConstructor.java:102)
    at sun.jvm.hotspot.oops.Metadata.instantiateWrapperFor(Metadata.java:68)
    at sun.jvm.hotspot.memory.DictionaryEntry.klass(DictionaryEntry.java:71)
    at sun.jvm.hotspot.memory.Dictionary.classesDo(Dictionary.java:66)
    at sun.jvm.hotspot.memory.SystemDictionary.classesDo(SystemDictionary.java:190)
    at sun.jvm.hotspot.memory.SystemDictionary.allClassesDo(SystemDictionary.java:183)
    at sun.jvm.hotspot.utilities.HeapHprofBinWriter.writeClasses(HeapHprofBinWriter.java:954)
    at sun.jvm.hotspot.utilities.HeapHprofBinWriter.write(HeapHprofBinWriter.java:427)
    at sun.jvm.hotspot.tools.HeapDumper.run(HeapDumper.java:62)
    at sun.jvm.hotspot.tools.Tool.startInternal(Tool.java:260)
    at sun.jvm.hotspot.tools.Tool.start(Tool.java:223)
    at sun.jvm.hotspot.tools.Tool.execute(Tool.java:118)
    at sun.jvm.hotspot.tools.HeapDumper.main(HeapDumper.java:83)

Answer 1

I too faced this issue with openjdk8 alpine. Worked fine on upgrading base image to openjdk:17-jdk-alpine