JRockit jrcmd command is very useful for debugging issues i nthe JVM

usage:

 jrcmd

 

the processid is 5176 here in this example

 jrcmd 5176 help

The following commands are available:

 kill_management_server

 start_management_server

 print_object_summary

 memleakserver

 print_class_summary

 print_codeblocks

 dump_codelayout

 dump_codelist

 dump_codemap

 print_codegenlist

 print_vm_state

 print_utf8pool

 check_flightrecording

 dump_flightrecording

 stop_flightrecording

 start_flightrecording

 print_properties

 hprofdump

 print_threads

 datadump_request

 runsystemgc

 runfinalization

 heap_diagnostics

 oom_diagnostics

 print_exceptions

 version

 timestamp

 command_line

 sanity

 verbosity

 set_filename

 help

 print_memusage

 set_vmflag

 list_vmflags

 For more information about a specific command use 'help <command>'.

 Parameters to commands are optional unless otherwise stated.

 jrcmd 5176 print_object_summary

 

5176:

--------- Detailed Heap Statistics: ---------

43.4% 3565k    33273  +3565k [C

9.8% 802k    34241   +802k java/lang/String

7.9% 645k     5906   +645k java/lang/Class

5.1% 419k     1447   +419k [I

3.9% 316k    13498   +316k java/util/HashMap$Entry

...

8206kB total ---

--------- End of Detailed Heap Statistics ---

 jrcmd 5176 print_class_summary

 

5176:

- Class Summary Information starts here

class java/lang/Object

*class jrockit/vm/Memset

*class jrockit/vm/StringMaker

*class org/eclipse/swt/internal/win32/GCP_RESULTS

*class org/eclipse/swt/internal/win32/SCRIPT_FONTPROPERTIES

*class org/eclipse/swt/internal/win32/EXTLOGFONTW

*class org/eclipse/swt/graphics/TextLayout$1$MetaFileEnumProc

.....

 jrcmd 5176 print_codeblocks

 

5176:

Codeblock type=0 start= 0x04750000 end=0x04760000 top=0x04750540 freelist=0

Codeblock type=2 start= 0x04770000 end=0x04790000 top=0x0478FFA3 freelist=4264

Codeblock type=2 start= 0x04DD0000 end=0x04DF0000 top=0x04DEFFEB freelist=421

Codeblock type=2 start= 0x05170000 end=0x05190000 top=0x0518FFF0 freelist=466

....

 jrcmd 5176 print_codegenlist

 

5176:

JIT queue length: 0

Opt queue length: 0

 jrcmd 5176 print_vm_state

 

</pre>
CPU          : Intel Core 2 SSE SSE2 SSE3 SSSE3 Core Intel64

Number CPUs  : 2

Tot Phys Mem : 2136891392 (2037 MB)

OS version   : Microsoft Windows XP version 5.1 Service Pack 3 (Build 2600) (32-bit)

Thread System: Windows Threads

Java locking : Lazy unlocking enabled (class banning) (transfer banning)

State        : JVM is running

Command Line : -Denv.class.path=.;C:\Program Files\Java\jre6\lib\ext\QTJava.zip -Dapplication.home=C:\Program Files\Java\jrockit-jdk1.6.0_20-R28.1.0-4.0.1 -client -Dsun.java.launcher=SUN_STANDARD com.jrockit.mc.rcp.start.MCMain

...

GC Strategy  : Mode: pausetime, with strategy: singleconcon (basic strategy: singleconcon)

GC Status    : OC is not running. Last finished OC was OC#41.

Heap         : 0x10040000 - 0x12E78000  (Size: 46 MB)

Heap History : OC#14      - 0x11040000  (16 MB -> 19 MB; +3280 KB)

: OC#18      - 0x11374000  (19 MB -> 24 MB; +4400 KB)

: OC#21      - 0x117C0000  (24 MB -> 27 MB; +3320 KB)

: OC#26      - 0x11AFE000  (27 MB -> 32 MB; +5480 KB)

: OC#27      - 0x12058000  (32 MB -> 39 MB; +6576 KB)

: OC#28      - 0x126C4000  (39 MB -> 46 MB; +7888 KB)

Compaction   : (no compaction area)

Allocation   : TLA-min: 2048, TLA-preferred: 16384 TLA-waste limit: 2048

CompRefs     : References are 32-bit.

Loaded modules:

00400000-0043afff  C:\Program Files\Java\jrockit-jdk1.6.0_20-R28.1.0-4.0.1\bin\jrmc.exe

7c900000-7c9b1fff  C:\WINDOWS\system32\ntdll.dll

....

 jrcmd 5176 print_properties

 

5176:

=== Initial Java properties: ===

java.vm.specification.name=Java Virtual Machine Specification

java.vm.vendor.url.bug=http://download.oracle.com/docs/cd/E15289_01/go2troubleshooting.html

java.home=C:\Program Files\Java\jrockit-jdk1.6.0_20-R28.1.0-4.0.1\jre

java.vm.vendor.url=http://www.oracle.com/

java.vm.specification.version=1.0

java.vm.info=compiled mode

=== End Initial Java properties ===

=== VM properties: ===

jrockit.vm=C:\Program Files\Java\jrockit-jdk1.6.0_20-R28.1.0-4.0.1\jre\bin\jrockit\jvm.dll

jrockit.vm.dir=C:\Program Files\Java\jrockit-jdk1.6.0_20-R28.1.0-4.0.1\jre\bin\jrockit

=== End VM properties ===

=== Current Java properties: ===

Could not find fields=== End Current Java properties ===

 jrcmd 5176 print_threads

 

5176:

===== FULL THREAD DUMP ===============

Thu Jan 27 11:27:48 2011

Oracle JRockit(R) R28.1.0-123-138454-1.6.0_20-20101014-1351-windows-ia32

"Main Thread" id=1 idx=0x4 tid=3836 prio=6 alive, in native

at org/eclipse/swt/internal/win32/OS.WaitMessage()Z(Native Method)

at org/eclipse/swt/widgets/Display.sleep(Display.java:4281)

...

-- end of trace

"(Signal Handler)" id=2 idx=0x8 tid=4692 prio=5 alive, native_blocked, daemon

"(OC Main Thread)" id=3 idx=0xc tid=3512 prio=5 alive, native_waiting, daemon

..

-- end of trace

"Reference Handler" id=9 idx=0x2c tid=5472 prio=10 alive, native_waiting, daemon

at java/lang/ref/Reference.waitForActivatedQueue(J)Ljava/lang/ref/Reference;(Native Method)

..

-- end of trace

"(Sensor Event Thread)" id=10 idx=0x30 tid=2724 prio=5 alive, native_blocked, daemon

"VM JFR Buffer Thread" id=11 idx=0x34 tid=5912 prio=5 alive, in native, daemon

"State Data Manager" id=13 idx=0x38 tid=5732 prio=5 alive, sleeping, native_waiting, daemon

..

-- end of trace

"Start Level Event Dispatcher" id=14 idx=0x3c tid=5644 prio=5 alive, waiting, native_blocked, daemon

-- Waiting for notification on: org/eclipse/osgi/framework/eventmgr/EventManager$EventThread@0x107D7B48[fat lock]

..

-- end of trace

"Framework Event Dispatcher" id=15 idx=0x40 tid=4640 prio=5 alive, waiting, native_blocked, daemon

-- Waiting for notification on: org/eclipse/osgi/framework/eventmgr/EventManager$EventThread@0x10E1A6D0[fat lock]

...

-- end of trace

"[RJMX] JDP Client" id=17 idx=0x44 tid=5596 prio=5 alive, in native

at java/net/PlainDatagramSocketImpl.receive0(Ljava/net/DatagramPacket;)V(Native Method)

^-- Holding lock: java/net/PlainDatagramSocketImpl@0x10988A80[recursive]

..

-- end of trace

"Java2D Disposer" id=19 idx=0x4c tid=4352 prio=10 alive, waiting, native_blocked, daemon

-- Waiting for notification on: java/lang/ref/ReferenceQueue$Lock@0x10D0EB30[fat lock]

..

-- end of trace

"AWT-Windows" id=21 idx=0x54 tid=3088 prio=6 alive, in native, daemon

at sun/awt/windows/WToolkit.eventLoop()V(Native Method)

..

-- end of trace

"JMAPI event thread" id=27 idx=0x68 tid=5232 prio=5 alive, in native, daemon

"JFR request timer" id=28 idx=0x6c tid=6056 prio=6 alive, waiting, native_blocked, daemon

-- Waiting for notification on: java/util/TaskQueue@0x1008DCE0[fat lock]

at jrockit/vm/Threads.waitForNotifySignal(JLjava/lang/Object;)Z(Native Method)

...

-- end of trace

"Worker-0" id=30 idx=0x70 tid=252 prio=5 alive, waiting, native_blocked

-- Waiting for notification on: org/eclipse/core/internal/jobs/WorkerPool@0x10DD48A0[fat lock]

at jrockit/vm/Threads.waitForNotifySignal(JLjava/lang/Object;)Z(Native Method)

...

-- end of trace

"Local Descriptor Scanner" id=31 idx=0x74 tid=2280 prio=6 alive, sleeping, native_waiting

at java/lang/Thread.sleep(J)V(Native Method)

..

"JDP Stale Descriptor Detector" id=32 idx=0x78 tid=4788 prio=6 alive, sleeping, native_waiting

at java/lang/Thread.sleep(J)V(Native Method)

..

-- end of trace

===== END OF THREAD DUMP ===============

 jrcmd 5176 heap_diagnostics

 

5176:

Invoked from diagnosticcommand

======== BEGIN OF HEAPDIAGNOSTIC =========================

Total memory in system: 2136891392 bytes

Available physical memory in system: 179638272 bytes

-Xmx (maximal heap size) is 1073741824 bytes

Heapsize: 48463872 bytes

Free heap-memory: 19064600 bytes

--------- Detailed Heap Statistics: ---------

44.3% 3375k    30871   -190k [C

9.8% 745k    31818    -56k java/lang/String

8.5% 645k     5906     +0k java/lang/Class

5.5% 417k     1378     -1k [I

3.8% 292k      237     +0k [B

3.6% 272k    11637    -43k java/util/HashMap$Entry

2.4% 179k     2234    -21k [Ljava/util/HashMap$Entry;

2.3% 171k     2585     -8k [Ljava/lang/Object;

1.4% 103k     2213    -27k java/util/HashMap

1.0% 72k     3114     +0k java/util/Hashtable$Entry

.....

7619kB total ---

--------- End of Detailed Heap Statistics ---

----- Reference Objects statistics separated per class -----

Total Reach Act PrevAct Null

----- ----- --- ------- ----

Soft References:

1456    60   0     971  425 Total for all Soft References

org/eclipse/core/internal/registry/ReferenceMap$SoftRef =>

974    12   0     962    0 Total

962     0   0     962    0 => null

12    12   0       0    0 => org/eclipse/osgi/framework/internal/core/BundleHost

java/lang/ref/SoftReference =>

430     5   0       0  425 Total

425     0   0       0  425 => null

2     2   0       0    0 => [Ljava/lang/reflect/Constructor;

1     1   0       0    0 => org/eclipse/osgi/internal/baseadaptor/DefaultClassLoader

1     1   0       0    0 => java/util/jar/Manifest

1     1   0       0    0 => java/lang/StringCoding$StringDecoder

java/util/ResourceBundle$BundleReference =>

48    40   0       8    0 Total

29    29   0       0    0 => java/util/ResourceBundle$1

11    11   0       0    0 => java/util/PropertyResourceBundle

8     0   0       8    0 => null

sun/security/util/MemoryCache$SoftCacheEntry =>

3     3   0       0    0 Total

3     3   0       0    0 => sun/security/x509/X509CertImpl

sun/misc/SoftCache$ValueCell =>

1     0   0       1    0 Total

1     0   0       1    0 => null

Weak References:

2982  2614   0     173  195 Total for all Weak References

java/lang/ref/WeakReference =>

1705  1510   0       0  195 Total

796   796   0       0    0 => java/lang/String

327   327   0       0    0 => java/lang/Class

....

java/util/WeakHashMap$Entry =>

1130   958   0     172    0 Total

796   796   0       0    0 => java/lang/String

172     0   0     172    0 => null

..

java/util/ResourceBundle$LoaderReference =>

48    48   0       0    0 Total

39    39   0       0    0 => org/eclipse/osgi/internal/baseadaptor/DefaultClassLoader

9     9   0       0    0 => java/util/ResourceBundle$RBClassLoader

java/lang/ThreadLocal$ThreadLocalMap$Entry =>

38    38   0       0    0 Total

20    20   0       0    0 => java/lang/ThreadLocal

11    11   0       0    0 => java/lang/InheritableThreadLocal

4     4   0       0    0 => org/eclipse/ui/internal/UISynchronizer$2

2     2   0       0    0 => sun/misc/FloatingDecimal$1

1     1   0       0    0 => org/eclipse/ui/internal/UISynchronizer$1

org/eclipse/core/internal/runtime/ReferenceHashSet$HashableWeakReference =>

35    35   0       0    0 Total

12    12   0       0    0 => org/eclipse/ui/internal/registry/ViewDescriptor

6     6   0       0    0 => org/eclipse/ui/internal/registry/ActionSetDescriptor

...

com/sun/jmx/mbeanserver/WeakIdentityHashMap$IdentityWeakReference =>

15    15   0       0    0 Total

3     3   0       0    0 => sun/management/MemoryPoolImpl

2     2   0       0    0 => sun/management/GarbageCollectorImpl

1     1   0       0    0 => sun/management/RuntimeImpl

...

com/sun/java/swing/plaf/windows/DesktopProperty$WeakPCL =>

6     6   0       0    0 Total

4     4   0       0    0 => com/sun/java/swing/plaf/windows/WindowsLookAndFeel$TriggerDesktopProperty

1     1   0       0    0 => com/sun/java/swing/plaf/windows/WindowsLookAndFeel$FontDesktopProperty

1     1   0       0    0 => com/sun/java/swing/plaf/windows/WindowsLookAndFeel$WindowsFontProperty

sun/nio/ch/FileChannelImpl$FileLockReference =>

4     4   0       0    0 Total

4     4   0       0    0 => sun/nio/ch/FileLockImpl

javax/swing/plaf/metal/MetalLookAndFeel$AATextListener =>

1     0   0       1    0 Total

1     0   0       1    0 => null

Phantom References:

2     2   0       0    0 Total for all Phantom References

java/lang/ref/PhantomReference =>

2     2   0       0    0 Total

2     2   0       0    0 => java/lang/Object

Cleared Phantom:

8     8   0       0    0 Total for all Cleared Phantom

jrockit/vm/ObjectMonitor =>

8     8   0       0    0 Total

2     2   0       0    0 => org/eclipse/osgi/framework/eventmgr/EventManager$EventThread

1     1   0       0    0 => org/eclipse/core/internal/jobs/WorkerPool

...

Finalizers:

161   161   0       0    0 Total for all Finalizers

68    68   0       0    0 => java/util/zip/ZipFile

44    44   0       0    0 => java/util/zip/Inflater

...

Weak Handles:

8311  8311   0       0    0 Total for all Weak Handles

6052  6052   0       0    0 => org/eclipse/osgi/internal/baseadaptor/DefaultClassLoader

1397  1397   0       0    0 => java/lang/String

594   594   0       0    0 => org/eclipse/equinox/launcher/Main$StartupClassLoader

..

Soft reachable referents not used for at least 201.708 s cleared.

3 SoftReferences was soft alive but not reachable (when found by the GC),

0 was both soft alive and reachable, and 1453 was not soft alive.

----- End of Reference Objects statistics -----

Dark matter: 509525593 bytes

Heap size is not locked

======== END OF HEAPDIAGNOSTIC ===========================

 jrcmd 5176 oom_diagnostics

 

similar to heap diagnostics

 jrcmd 5176 version

 

5176:

Oracle JRockit(R) build R28.1.0-123-138454-1.6.0_20-20101014-1351-windows-ia32, compiled mode

GC mode: Garbage collection optimized for short pausetimes, strategy: singleconcon

 jrcmd 5176 print_memusage

 

5176:

Total mapped                  1242224KB           (reserved=1074256KB)

-              Java heap      1048576KB           (reserved=1001248KB)

-              GC tables        35084KB

-          Thread stacks        10752KB           (#threads=24)

-          Compiled code         3968KB           (used=3812KB)

-               Internal          968KB

-                     OS        43488KB

-                  Other        70588KB

-        Java class data        27776KB           (malloced=27745KB #32965 in 5906 classes)

- Native memory tracking         1024KB           (malloced=361KB #8)

 jrcmd 5176 print_vmflags

 

5176:

Global:

UnlockDiagnosticVMOptions = false (default, writeable)

UnlockInternalVMOptions = false (default)

Class:

FailOverToOldVerifier = true (default, writeable)

UseVerifierClassCache = true (default)

UseClassGC = true (default)

Threads:

UseThreadPriorities = false (default)

DeferThrSuspendLoopCount = 4000 (default, writeable)

SafepointSpinBeforeYield = 2000 (default, writeable)

UseCompilerSafepoints = true (default)

DeferPollingPageLoopCount = -1 (default)

UseMembarForTransitions = false (default)

UseNativeLockProfiling = false (default)

JNI:

CheckJNICalls = false (default)

AbortOnFailedJNICheck = true (default)

ErrorOnFailedJNICheck = false (default)

JDK:

UseNewHashFunction = false (default)

TreeMapNodeSize = 64 (default)

MaxDirectMemorySize = 0 (default)

UseLazyStackTraces = true (default)

ShowInternalMethodsInStackTrace = false (default, writeable)

OS:

ReduceSignalUsage = false (default)

MaxRecvBufferSize = 65536 (default)

MaxLargePageSize = 0 (default)

GC:

UseLowAddressForHeap = true (default)

UseLargePagesForHeap = false (default)

ForceLargePagesForHeap = false (default)

CompressedRefs = false (default)

InitialHeapSize = 0 (default)

MaxHeapSize = 0 (default)

GCTimeRatio = 19 (default)

GCTimePercentage = 0.000000 (default)

GCTrigger = 0 (default)

ForceEarlyOC = true (default)

ForceEarlyOCMaxPercentage = 5.000000 (default)

ForceYCOnLargeAllocationFailed = false (default)

UseNurseryEvacuation = false (default)

DisableEvacuationToNursery = false (default)

SemiRefPostponedPacketSize = 492 (default)

SemiRefPrefetchDistance = 0 (default)

FinalHandleParallelThreshold = 800 (default)

FinalHandlePacketSize = 200 (default)

MaximumNurseryPercentage = 95 (default)

AllowYCDuringOC = true (default)

YcAlignAll = false (default)

YcAlignMaxSpill = 40 (default)

FullSystemGC = false (default)

AllowSystemGC = true (default)

GcCardTableParts = 1024 (default)

GcBalancePrefetchDistance = 4 (default)

GcBalancePacketSize = 493 (default)

NumGenConPrecleaningIterations = 3 (default)

AllowEmergencyParSweep = true (default)

TlaWasteLimit = 2K (set by runtime)

TlaMinSize = 2K (set by runtime)

TlaPreferredSize = 16K (set by runtime)

GC::Compaction:

UseFullCompaction = false (default)

InternalCompactionPercentage = -1.000000 (default)

ExternalCompactionPercentage = -1.000000 (default)

InitialCompactionPercentage = -1.000000 (default)

UseCompaction = true (default)

UseAbortableCompaction = false (default)

NumCompactionHeapParts = 4096 (default)

InitialExternalReservedHeap = 4M (default)

UseFixedExternalReservedHeap = false (default)

MaxCompactionReferences = 0 (default)

MaxCompactionReferencesPerObject = 0 (default)

InternalCompactionParts = -1 (default)

ExternalCompactionParts = -1 (default)

Object allocation:

UseAllocPrefetch = true (default)

RedoAllocPrefetch = true (default)

AllocPrefetchLineLength = 64 (default)

AllocPrefetchDistance = 448 (default)

AllocChunkSize = 512 (default)

Javalock:

UseLockProfiling = false (default)

ThinLockContendedSpinCount = 65 (default)

ThinLockContendedPollCount = 50 (default)

ThinLockConvertToFatThreshold = 240 (default)

FatLockContendedSpinCount = 65 (default)

FatLockContendedPollCount = 50 (default)

MonitorContendedSpinCount = 50 (default)

MonitorContendedPollCount = 20 (default)

UseFatLockDeflation = true (default)

FatLockDeflationThreshold = 50 (default)

UseLockQueueLength = true (default)

UseFatSpin = true (default)

UseAdaptiveFatSpin = false (default)

UseThreadContentionMonitoring = true (default)

JavaLock::LazyUnlocking:

UseLazyUnlocking = true (default)

UseLazyUnlockingInJIT = true (default)

UseLazyUnlockingClassBan = true (default)

UseLazyUnlockingTransferClassBan = true (default)

JFR:

FlightRecorder = true (default)

FlightRecorderOptions = (null) (default)

StartFlightRecording = (null) (default)

Code memory:

CodeBlockAbsorbtionSize = 16 (default)

FreeEmptyCodeBlocks = true (default)

UseLargePagesForCode = false (default)

MaxCodeMemory = 0 (default)

ReserveCodeMemory = false (default)

UseCodeGC = true (default)

CodeGCThreshold = 0 (default)

CodeGCReclaimThreshold = 0 (default)

CodeGCUseReclaim = true (default)

Compiler broker:

MaxOptQueueLength = 0 (default)

OptThreads = 1 (default)

JITThreads = 1 (default)

JITThreadPrio = 5 (default)

OptThreadPrio = 5 (default)

DisableOptsAfter = -1 (default)

Compiler:

PreOpt = false (default)

UseCallProfiling = false (default)

StrictFP = false (default)

CheckStacks = false (default)

DevirtualizeAlways = false (default)

UseStringCache = false (default)

MethodCodeAlignment = 32 (default)

UseInlineObjectAlloc = true (default)

UseOldLockMatching = false (default)

JVMTI:

JavaDebug = false (default)

Management:

DisableAttachMechanism = false (default)

CrashOnOutOfMemoryError = false (default, writeable)

ExitOnOutOfMemoryError = false (default, writeable)

ExitOnOutOfMemoryErrorExitCode = 51 (default, writeable)

HeapDiagnosticsOnOutOfMemoryError = false (default, writeable)

HeapDiagnosticsPath = (null) (default, writeable)

HeapDumpOnOutOfMemoryError = false (default, writeable)

HeapDumpOnCtrlBreak = false (default)

HeapDumpPath = (null) (default, writeable)

SegmentedHeapDumpThreshold = 2G (default, writeable)

HeapDumpSegmentSize = 1G (default)

StartMemleakOnPort = 0 (default, writeable)

FlightRecordingDumpOnUnhandledException = false (default, writeable)

FlightRecordingDumpPath = (null) (default, writeable)

Runtime:

AbortOnCrash = false (default, writeable)

DumpOnCrash = true (default, writeable)

CoreOnCrash = true (default, writeable)

WaitOnCrash = false (default, writeable)

AbortOnAssert = true (default, writeable)

CrashOnAssert = false (default, writeable)

WaitOnAssert = false (default, writeable)

NumaMemoryPolicy = (null) (default)

BindToNumaNodes = (null) (default)

BindToCPUs = (null) (default)

UseFastTime = true (default)

UseJNIPinning = true (default)