Can jconsole data be retrieved from the command line?

Question

I am currently using jconsole to monitor performance metrics of my Java application and would like to script this data acquisition.

Is there a way to retrieve these VM metrics (heap memory usage, thread count, CPU usage etc.) to STDOUT?
The data in top -p PID -b -n 1 doesn't quite cut it.

Thanks

Answer 1

jconsole just provides a wrapper around the JMX MBeans that are in the platform MBeanServer.

You can write a program to connect to your VM using the Attach API which would then query the MBeans.

Or you can expose the platform MBeanServer over RMI and query the MBeans that way.

See the java.lang.management package for more info

Answer 2

Maybe jvmtop is worth a look.
It's a command-line tool which provides a live-view for several metrics.

Example output of the VM overview mode:

 JvmTop 0.4.1  amd64  8 cpus, Linux 2.6.32-27, load avg 0.12
 http://code.google.com/p/jvmtop

  PID MAIN-CLASS      HPCUR HPMAX NHCUR NHMAX    CPU     GC    VM USERNAME   #T DL
 3370 rapperSimpleApp  165m  455m  109m  176m  0.12%  0.00% S6U37 web        21
11272 ver.resin.Resin [ERROR: Could not attach to VM]
27338 WatchdogManager   11m   28m   23m  130m  0.00%  0.00% S6U37 web        31
19187 m.jvmtop.JvmTop   20m 3544m   13m  130m  0.93%  0.47% S6U37 web        20
16733 artup.Bootstrap  159m  455m  166m  304m  0.12%  0.00% S6U37 web        46

Answer 3

Take a look at jmap, which can be used to take a heap dump from the console.

For data not covered in the heap dump, I believe jconsole just uses JMX to connect to the running JVM to get statistics - so it's likely possible to create your own application which could pull those same types of stats from JMX.

Answer 4

You can use this jmx query tool by command line: http://crawler.archive.org/cmdline-jmxclient/

Answer 5

Some other useful CLI tools to monitor a Java applications are:

• Jmxterm which gives full access to all MBeans on the application server, runs interactively or not,
• jmxbox which can only connect through a TCP socket, not directly to a local process with its PID

Answer 6

You might find jvm-mon useful for this. It is a JVM monitoring tool for the command line that disaplys:

• jvm processes
• cpu and GC usage
• heap usage and size
• top threads

The metrics and charts update while the tool is open.

Sample:

Answer 7

jstack offers a number of useful bits of information in its normal output. Heap memory usage is directly available, broken down by GC region; thread count could be determined with a little bit of perl / grep / etc.

Answer 8

This is a partial answer to your question:

set JAVA_OPTS=%JAVA_OPTS% -Xloggc:logs\gc.log -XX:+PrintGCDetails -XX:MaxPermSize=128m 

Answer 9

I have successfully used the tomcat jmxproxy for access from scripts ( http://tomcat.apache.org/tomcat-6.0-doc/manager-howto.html#Using_the_JMX_Proxy_Servlet ).

I haven't used any of them but one of the jmx-rest projects might be an option for a non-tomcat server ( http://www.google.com/search?q=jmx+rest ).