Hung,
Dejava.lang.OutOfMemoryError: nativeGetNewTLAadlocked, or Looping
Process
Print
thread stack for all Java threads:
Control-\
kill
-QUIT pid
jstack pid (or jstack
-F pid if jstack pid does
not respond)
Detect
deadlocks:
Request
deadlock detection: JConsole tool, Threads tab
Print
information on deadlocked threads: Control-\
Print
list of concurrent locks owned by each
thread: -XX:+PrintConcurrentLocks set,
then Control-\
Print
lock information for a process: jstack
-l pid
Get
a heap histogram for a process:
Start
Java process with -XX:+PrintClassHistogram,
then Control-\
jmap
-histo pid (with -F option
if pid does
not respond)
Dump
Java heap for a process in binary format to file:
jmap
-dump:format=b,file= filename
pid (with -F option
if pid does
not respond)
Print
shared object mappings for a process:
jmap pid
Print
heap summary for a process:
Control-\
jmap
-heap pid
Print
finalization information for a process:
jmap
-finalizerinfo pid
Attach
the command-line debugger to a process:
jdb
-connect sun.jvm.hotspot.jdi.SAPIDAttachingConnector:pid= pid
Post-mortem
Diagnostics, Memory Leaks
- Examine the fatal error log file. Default file name is hs_err_pid pid .log in the working-directory.
- Create a heap dump:
- Start the application with HPROF enabled: java -agentlib:hprof=file= file,format=b application; then Control-\
- Start the application with HPROF enabled: java -agentlib:hprof=heap=dumpapplication
- JConsole tool, MBeans tab
- Start VM with -XX:+HeapDumpOnOutOfMemoryError; if OutOfMemoryError is thrown, VM generates a heap dump.
- Browse Java heap dump:
- jhat heap-dump-file
- Dump Java heap from core file in binary format to a file:
- jmap -dump:format=b,file= filename corefile
- Get a heap histogram for a process:
- Start Java process with -XX:+PrintClassHistogram, then Control-\
- jmap -histo pid (with -F option if pid does not respond)
- Get a heap histogram from a core file:
- jmap -histo corefile
- Print shared object mappings from a core file:
- jmap corefile
- Print heap summary from a core file:
- jmap -heap corefile
- Print finalization information from a core file:
- jmap -finalizerinfo corefile
- Print Java configuration information from a core file:
- jinfo corefile
- Print thread trace from a core file:
- jstack corefile
- Print lock information from a core file:
- jstack -l corefile
- Attach the command-line debugger to a core file on the same machine:
- jdb -connect sun.jvm.hotspot.jdi.SACoreAttachingConnector:javaExecutable= path,core= corefile
- Attach the command-line debugger to a core file on a different machine:
- On the machine with the core file: jsadebugd path corefile
and on the machine with the debugger: jdb -connect sun.jvm.hotspot.jdi.SADebugServerAttachingConnector:debugServerName=machine
- libumem can be used to debug memory leaks.
Monitoring
Note:
The vmID argument
for the jstat command is the virtual machine identifier.
- Print statistics on the class loader:
- jstat -class vmID
- Print statistics on the compiler:
- Compiler behavior: jstat -compiler vmID
- Compilation method statistics: jstat -printcompilation vmID
- Print statistics on garbage collection:
- Summary of statistics: jstat -gcutil vmID
- Summary of statistics, with causes: jstat -gccause vmID
- Behavior of the gc heap: jstat -gc vmID
- Capacities of all the generations: jstat -gccapacity vmID
- Behavior of the new generation: jstat -gcnew vmID
- Capacity of the new generation: jstat -gcnewcapacity vmID
- Behavior of the old and permanent generations: jstat -gcold vmID
- Capacity of the old generation: jstat -gcoldcapacity vmID
- Capacity of the permanent generation: jstat -gcpermcapacity vmID
- Monitor objects awaiting finalization:
- JConsole tool, VM Summary tab
- jmap -finalizerinfo pid
- getObjectPendingFinalizationCount method injava.lang.management.MemoryMXBean class
- Monitor memory:
- Heap allocation profiles via HPROF: java -agentlib:hprof=heap=sites
- JConsole tool, Memory tab
- Control-\ prints generation information.
- Monitor CPU usage:
- By thread stack: java -agentlib:hprof=cpu=samples application
- By method: java -agentlib:hprof=cpu=times application
- JConsole tool, Overview and VM Summary tabs
- Monitor thread activity:
- JConsole tool, Threads tab
- Monitor class activity:
- JConsole tool, Classes tab
Actions
on a Remote Debug Server
First,
attach the debug daemon jsadebugd, then execute the command:
- Dump Java heap in binary format to a file: jmap -dump:format=b,file= filename hostID
- Print shared object mappings: jmap hostID
- Print heap summary : jmap -heap hostID
- Print finalization information : jmap -finalizerinfo hostID
- Print lock information : jstack -l hostID
- Print thread trace : jstack hostID
- Print Java configuration information: jinfo hosted
- Interface with the instrumented Java virtual machines:
- Monitor for the creation and termination of instrumented VMs: jstatd daemon
- List the instrumented VMs: jps
- Provide interface between remote monitoring tools and local VMs: jstatd daemon
- Request garbage collection: JConsole tool, Memory tab
- Print Java configuration information from a running process:
- jinfo pid
- Dynamically set, unset, or change the value of certain Java VM flags for a process:
- jinfo -flag flag
- Print command-line flags passed to the VM:
- jinfo -flags
- Print Java system properties:
- jinfo -sysprops
- Pass a Java VM flag to the virtual machine:
- jconsole -J flag ...
- jhat -J flag ...
- jmap -J flag ...
- Print statistics of permanent generation of Java heap, by class loader:
- jmap -permstat
- Report on monitor contention.
- java -agentlib:hprof=monitor=y application
- Evaluate or execute a script in interactive or batch mode:
- jrunscript
- Interface dynamically with an MBean, via JConsole tool, MBean tab:
- Show tree structure.
- Set an attribute value.
- Invoke an operation.
- Subscribe to notification.
- Run interactive command-line debugger:
- Launch a new VM for the class: jdb class
- Attach debugger to a running VM: jdb -attach address
From
oracle, More to Come
