Tracing Javaws launch

Question

I have a Java application which is launched via Java Webstart. Occasionally, following a new deployment of the application, it will happen that launching the application results in it being downloaded twice on every launch. I haven't got to the bottom of this but I think it may be related to our squid proxy which seems to interact badly with Java. What I would like, in order to investigate this further, is to see a trace of what javaws is doing. Is there any such option available to javaws?

Just a minor update, if Java is configured to show the console then hitting "5" when focussed on the console will set the logging level to 5 which is the most verbose logging level. This can be useful but it doesn't address cases where the application doesn't get this far.

Solution 1

To enable full trace mode issue the following commands in a command line:

"C:\Program Files (x86)\Java\jre8\bin\javaws.exe" -userConfig deployment.trace true
"C:\Program Files (x86)\Java\jre8\bin\javaws.exe" -userConfig deployment.trace.level all

The trace files will be placed in %USERPROFILE%\AppData\LocalLow\Sun\Java\Deployment\log.

To disable full trace mode again:

"C:\Program Files (x86)\Java\jre8\bin\javaws.exe" -userConfig deployment.trace
"C:\Program Files (x86)\Java\jre8\bin\javaws.exe" -userConfig deployment.trace.level

Solution 2

You may either want to run the jnlp file with -verbose option via javaws command from the command line and/or check the logs. The logs location is java version dependant, In earlier windows releases default path was: c:\Documents and Settings\_user_\Application Data\Sun\Java\Deployment\log

In Windows 7,default path is 'C:\Users\_user_\AppData\LocalLow\Sun\Java\Deployment\log'

Comments

[PhilDin]

Hi Jan, thanks for your suggestion (sorry, I just noticed it until now). Unfortunately, the verbose option and the logs in the deployment folder don't show the information that I was looking for. Specifically, I was trying the see what versions of what jars were being downloaded by javaws and why (I don't have the jar vs. I do have it but it's out of date). The logs in the deployment folder show application logs as opposed to the output of the JNLP process. Thanks for the suggestion though.