JDK not so hidden treasures

Andrzej Grzesik

@ags313

andrzej@grzesik.it

andrzejgrzesik.info

about:me

dev going deeper

java

If Java had true garbage collection, most programs would delete themselves upon execution

Robert Sewell

tl;dr: log gc at least

every known problem becomes completely new

when you add “in Java”

stolen from: @mryapee

javac

javap

when things go…

does it run?

top // htop

jpsinstead of ps

jar

jmapinstead of pmap

and jhat

stacktraces :)

kill -3 <pid>

caveat ;-)

jstack

quiz time

caveatsonly at safepoints, one thread at a time

jstat

custom optionshttp://hg.openjdk.java.net/jdk9/jdk9/jdk/file/d49e247dade6/src/jdk.jcmd/share/

classes/sun/tools/jstat/resources/jstat_options

jstatd

from http://www.slideshare.net/stalar/diagnosing-your-application-on-the-jvm

jcmd

jmxsh

jmxtermhttp://wiki.cyclopsgroup.org/jmxterm

http://code.google.com/p/jmxsh/

and more

jvisualvm