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2

We have an open beta of an app which occasionally causes the heapspace to overflow. The JVM reacts by going on a permanent vacation.

To analyze this I would like to peek into the memory at the point where it failed. Java does not want me to do this. The process is still in memory but it doesn't seem to be recognized as a java process.

The server in question is a debian Lenny server, Java 6u14

/opt/jdk/bin# ./jmap -F -dump:format=b,file=/tmp/apidump.hprof 11175 Attaching to process ID 11175, please wait... sun.jvm.hotspot.debugger.NoSuchSymbolException: Could not find symbol "gHotSpotVMTypeEntryTypeNameOffset" in any of the known library names (libjvm.so, libjvm_g.so, gamma_g) at sun.jvm.hotspot.HotSpotTypeDataBase.lookupInProcess(HotSpotTypeDataBase.java:390) at sun.jvm.hotspot.HotSpotTypeDataBase.getLongValueFromProcess(HotSpotTypeDataBase.java:371) at sun.jvm.hotspot.HotSpotTypeDataBase.readVMTypes(HotSpotTypeDataBase.java:102) at sun.jvm.hotspot.HotSpotTypeDataBase.<init>(HotSpotTypeDataBase.java:85) at sun.jvm.hotspot.bugspot.BugSpotAgent.setupVM(BugSpotAgent.java:568) at sun.jvm.hotspot.bugspot.BugSpotAgent.go(BugSpotAgent.java:494) at sun.jvm.hotspot.bugspot.BugSpotAgent.attach(BugSpotAgent.java:332) at sun.jvm.hotspot.tools.Tool.start(Tool.java:163) at sun.jvm.hotspot.tools.HeapDumper.main(HeapDumper.java:77) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at sun.tools.jmap.JMap.runTool(JMap.java:179) at sun.tools.jmap.JMap.main(JMap.java:110) Debugger attached successfully. sun.jvm.hotspot.tools.HeapDumper requires a java VM process/core!

A: 

What happens if you just run

./jmap -heap 11175 

And are you sure the application JVM is identical to the JMAP JVM? (same version, etc)

bwawok
A: 

The solution was very simple. I was running the jmap as root, but I had to run it as the user who started the jvm. I will now go hide my head in shame.

Jasper Floor