Monitoring used Java memory

[xarous]

I'm trying to monitor the Used Java memory in WildFly8 using JMX.

Currently I have the following options -

Using jboss-cli

C:\wildfly-8.2.1.Final\bin\jboss-cli --connect command='/core-service=platform-mbean/type=memory/ :read-attribute(name=heap-memory-usage)'

Using standalone twiddle

"C:\Program Files (x86)\twiddle\bin\twiddle.bat" -s service:jmx:http-remoting-jmx://localhost:9990 get --noprefix jboss.as:core-service=platform-mbean,type=memory heap-memory-usage

but they return a structure e.g.

{

    "outcome" => "success",

    "result" => {

        "init" => 134217728L,

        "used" => 804574352L,

        "committed" => 918552576L,

        "max" => 1431830528L

    }

}

Is there a way to pull just the "used" number directly?

[xarous]

I've got a workaround using powershell to pull the value from the structure.

powershell.exe -command "$output = $(C:\Progra~2\twiddle\bin\twiddle.bat -s service:jmx:http-remoting-jmx://localhost:9990 get --noprefix jboss.as:core-service=platform-mbean`,type=memory heap-memory-usage | select-string 'used') ; $output -replace '.*used=' -replace '\}.*'"

[ctomc]

why don't you collect memory info directly from jdk via jmx? It looks quite bit of roundtrip if you could access jdk's memory info directly.

see more on that at:

Monitoring and Management Using JMX Technology - Java SEMonitoring and Management Guide

on cli topic you are mentioning, starting with version 9, you could use enhanced syntax for reading complex attributes like this.

where command would then look like

/core-service=platform-mbean/type=memory/:read-attribute(name=heap-memory-usage.used)