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Swiss Java Knife

SJK is a command line tool for JVM diagnostic, troubleshooting and profiling.

Prebuild binaries (2013-09-06) are below, though I would encourge you to build jars from sources.

Starting sjk

java -jar sjk.jar <cmd> <arguments>
java -jar sjk.jar --help
java -jar sjk.jar --help <cmd>

Below a few command

ttop

Pools thread CPU usage of target JVM and periodically report to console.

  • Could sort thread by CPU usage and/or thread's name.
  • Could limit number of thread displayed
  • Display thread memory allocation rate and cumulative process allocation rate (if supported by JVM)

jps

Similar to jps.

  • Plus could filter process java processes by their system properties.
  • Plus could display specific system properties of process in output.
  • Plus could display values of specific -XX for HotSpot JVM processes.

hh

Similar to jmap -histo.

  • Plus can show histogram of dead objects (histograms of all and live requested, then difference is caluclated).
  • Plus can show N top buckets in histogram.

gcrep

Report information about GC in real time. Data is retrieved via JMX.

mx

This command allow you to do basic operations with MBean from command line.

It can

  • read MBean attributes
  • update MBean writeable attributes
  • invoke MBean operations (arguments are supported)
  • displays composite and tabular data in human readable format
  • use wild cards to shorten MBean names (e.g. *:*,name=CodeCacheManager instead of java.lang:type=MemoryManager,name=CodeCacheManager)
  • connect to local JVM processes by PID (e.i. any Java process, you do not need to enable JMX server)
  • connect to JMX using host:port (password authentication is supported)

More details

mxdump

Dumps all MBeans of target java process to JSON.