MacOS – Why is Java consuming 100% CPU on the machine

javamacos

I have an iMac (early 2010) running 10.7.2 but the problem has been seen on 10.6.x also. The symptom is simple, one of my 2 cores is sitting at 100% utilization with the Java process responsible for the excessive usage.

What have I done to troubleshoot?

  • Reboot – The java process simply restarts and the same condition is seen.
  • Kill the Java process – As with a reboot.
  • Uninstall and reinstall Java – Soon after installing Java the CPU is back at 100%.

  • Using ps "process id" I can see that it is launchd spawning the process and that the command used to start the process is:

    java -Djava.awt.headless=true -jar /tmp/ics29586

  • The ics29586 file is an 11mb binary file.

  • Deleted the ics29586 file – File is recreated at next process restart and same condition is seen
  • Created a new user account, rebooted and logged in as the new user – Same condition is seen.
  • Played with Java settings and restarted the process after each change – Same condition seen.
  • Complete machine rebuild – Soon after installing Java the CPU is back at 100%.

So, has anyone either got the the answer for what is causing it and how to fix it, or some advice on ways of further troubleshooting the issue?

In response to some of the comments asking for more info:

  • I'm not running crashplan.

  • I couldn't work out how to get Activity Monitor to show me open files, but googling suggested LSOF was a good match for what you wanted to know. It showed no open files:

    Deep-Desk:LaunchAgents photo$ sudo lsof -c java
Deep-Desk:LaunchAgents photo$

  • There are 220 ports open for the Java process at present

  • The only file of interest in either the LaunchDaemons or LaunchAgents folders is:

    -rw-r--r--   1 root  wheel   568B 10 Mar  2011 com.microsoft.office.licensing.helper.plist

  • Everything else is either com.apple or has a date well after the problem first manifested. By way of a test I have renamed the com.microsoft file to old.com.microsoft but it made no difference. I also moved the file completely out the LaunchDaemons directory and that made no difference either, the process still respawns, hangs around not doing much for a few minutes, then goes out of control and consumes all the CPU on 1 core.

Best Answer

I don't know either, but here's how to find out more

In cases of entirely unknown binaries, strings(1) is often helpful in getting a hint about what the file might be

strings /tmp/ics29586 | less

Have a look through the output and see if it's anything familiar.

Failing that, find out which launchd job it is being launched from:

launchctl list|awk '{id=$3; print "### " id; system("launchctl list " id)}'|awk '/^###/ {id=$2} /.*ics29586.*/ {print id}'

This should output one or more job tags in the form of (for example) com.apple.scrod (and a few errors, which you can ignore).

Once you have the job tag(s), get the launchd config for a job by running:

launchctl list com.apple.scrod    # insert your tag instead

This (and the tag itself, which often contains an internet domain name in reverse notation) should give you some more information about what this process is. Feel free to post it here if you need further help.

Update: Forgot to mention this, but since it's a jar file, you can copy it somewhere and unzip it (jar files are really just zip files) and have a look at what sort of Java classes are in there.

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