Public bug reported:
1) The release of Ubuntu you are using, via 'lsb_release -rd' or System ->
About Ubuntu.
Description: Ubuntu 9.10
Release: 9.10
2) The version of the package you are using, via 'apt-cache policy packagename'
or by checking in Synaptic.
openjdk-6-jre:
Installed: 6b16-1.6.1-3ubuntu3
Candidate: 6b16-1.6.1-3ubuntu3
Version table:
*** 6b16-1.6.1-3ubuntu3 0
999 http://security.ubuntu.com karmic-security/main Packages
999 http://security.ubuntu.com karmic-updates/main Packages
100 /var/lib/dpkg/status
6b16-1.6.1-1ubuntu3 0
999 http://fi.archive.ubuntu.com karmic/main Packages
3) What you expected to happen
You can get memory map dump of a JVM instance with jmap tool, see
http://java.sun.com/javase/6/docs/technotes/tools/share/jmap.html. However,
this is broken in openjdk-6 in karmic and probably lucid too, because there was
no indication about the fix in changelog.
Example with Sun JDK 1.6.0_20-b02 which works correctly.
(11:18:18)(t...@pink-piggy)(~/Desktop/tcpmon-1.0-bin/build)$ jps
1700 TCPMon
1764 Jps
(11:18:12)(t...@pink-piggy)(~/Desktop/tcpmon-1.0-bin/build)$ jmap -heap 1700
Attaching to process ID 1700, please wait...
Debugger attached successfully.
Server compiler detected.
JVM version is 16.3-b01
using thread-local object allocation.
Mark Sweep Compact GC
Heap Configuration:
MinHeapFreeRatio = 40
MaxHeapFreeRatio = 70
MaxHeapSize = 922746880 (880.0MB)
NewSize = 5439488 (5.1875MB)
MaxNewSize = 17592186044415 MB
OldSize = 5439488 (5.1875MB)
NewRatio = 2
SurvivorRatio = 8
PermSize = 21757952 (20.75MB)
MaxPermSize = 88080384 (84.0MB)
Heap Usage:
New Generation (Eden + 1 Survivor Space):
capacity = 17301504 (16.5MB)
used = 15400960 (14.6875MB)
free = 1900544 (1.8125MB)
89.01515151515152% used
Eden Space:
capacity = 15400960 (14.6875MB)
used = 15400960 (14.6875MB)
free = 0 (0.0MB)
100.0% used
>From Space:
capacity = 1900544 (1.8125MB)
used = 0 (0.0MB)
free = 1900544 (1.8125MB)
0.0% used
To Space:
capacity = 1900544 (1.8125MB)
used = 0 (0.0MB)
free = 1900544 (1.8125MB)
0.0% used
tenured generation:
capacity = 38404096 (36.625MB)
used = 0 (0.0MB)
free = 38404096 (36.625MB)
0.0% used
Perm Generation:
capacity = 21757952 (20.75MB)
used = 13456432 (12.833053588867188MB)
free = 8301520 (7.9169464111328125MB)
61.84604139213102% used
4) What happened instead
Here's what happens with Ubuntu's broken openjdk-6:
(11:20:36)(t...@pink-piggy)(~/Desktop/tcpmon-1.0-bin/build)$ jps
1883 Jps
1863 TCPMon
(11:20:38)(t...@pink-piggy)(~/Desktop/tcpmon-1.0-bin/build)$ jmap 1863
Attaching to process ID 1863, 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.HeapSummary.main(HeapSummary.java:39)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:616)
at sun.tools.jmap.JMap.runTool(JMap.java:196)
at sun.tools.jmap.JMap.main(JMap.java:128)
Debugger attached successfully.
sun.jvm.hotspot.tools.HeapSummary requires a java VM process/core!
The problem is that some needed symbols are stripped from libjvm.so.
Installing openjdk-6-dbg package doesn't fix the issue and you shouldn't
need this huge package anyway for the functionality.
This bug has been encountered by RedHat, Fedora and OpenSUSE communities
and fixed in corresponding distros already. See the comments in the
following bug entries for more info.
https://bugzilla.redhat.com/show_bug.cgi?id=530402
https://bugzilla.redhat.com/show_bug.cgi?id=541548
https://bugzilla.novell.com/show_bug.cgi?id=530046
** Affects: openjdk-6 (Ubuntu)
Importance: Undecided
Status: New
--
jmap memory mapping tool is broken due to aggressive stripping of libjvm.so
https://bugs.launchpad.net/bugs/574997
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